[Association between digestive tract cancer and severity of coronary artery disease].

Objective: To evaluate the association between digestive tract cancer and anatomical severity of coronary artery disease. Methods: This study enrolled 142 patients with digestive tract cancer who underwent coronary angiography in the Department of Cardiology of the First Medical Center of Chinese PLA General Hospital from 2009 to 2020 as the cancer group. The patients in cancer group were matched with 426 non-cancer patients who underwent coronary angiography at our hospital during the same period in a 1∶3 ratio based on gender and age. All enrolled patients had no previous history of percutaneous coronary intervention or coronary artery bypass grafting surgery. The severity of coronary artery disease was documented and assessed using the SYNTAX score based on angiogram. High SYNTAX score (SXhigh) was defined as SYNTAX score≥22 (upper quartile), while low SYNTAX score (SXlow) was SYNTAX score<22. High NLR (NLRhigh) was NLR≥2.287 (median), while low NLR (NLRlow) was NLR<2.287. The association between digestive tract cancer and severity of coronary artery disease was analyzed using logistic regression analysis. Results: This study included a total of 568 patients, with a mean age of (66.6±8.7) years. Among them, 430 patients (75.7%) were male. The cancer group consisted of 142 patients with digestive tract cancers, with a mean age of (66.5±8.4) years. The non-cancer group consisted of 426 patients, with a mean age of (66.7±8.8) years. The proportion of SXhigh in patients with digestive tract cancers (33.1%, 47 patients) was higher than that in non-cancer patients (23.9%, 102 patients) (P=0.032). Compared to non-cancer patients, SXhigh in patients with digestive tract cancers was higher (OR: 1.614, 95%CI: 1.051-2.481, P=0.029). Subgroup analysis stratified by NLR levels revealed that in the NLRhigh group, patients with digestive tract cancers exhibited a higher severity of coronary artery disease compared to non-cancer patients, with an OR of 1.948 (95%CI: 1.005-3.779, P=0.048). In the NLRlow group, there was no significant relationship between digestive tract cancers and the severity of coronary artery disease, with an OR of 1.277 (95%CI: 0.586-2.781, P=0.538). Conclusions: Digestive tract cancer is associated with the severity of coronary artery disease, and patients with digestive tract cancers have a higher risk of severe coronary artery disease than non-cancer patients. Additionally, there is an association between digestive tract cancers and the severity of coronary artery disease under conditions of high levels of inflammation.

[Factors associated with long-term survival in critically ill patients following surgery for solid tumors complicated with paraneoplastic pemphigus].

OBJECTIVE: Critically ill patients with solid tumors complicated with paraneoplastic pemphigus are usually treated in intensive care units (ICU) for perioperative management after surgical treatment. In this study, the clinical characteristics and predictors of long-term prognosis of these critically ill patients were analyzed. METHODS: the clinical and laboratory data of 63 patients with solid tumors complicated with paraneoplastic pemphigus admitted to ICU from 2005 to 2020 were retrospectively analyzed, and the survival status of the patients were followed up. RESULTS: Among the 63 patients, 79.4% had Castleman disease as the primary tumor, and 20.6% with other pathological types; 69.8% had severe-extensive skin lesions, and 30.2% had other skin lesions; the patients with bronchiolitis obliterans accounted for 44.4%, and 55.6% were not merged. Postoperative fungal infection occurred in 23.8% of the patients, and 76.2% without fungal infection. The median follow-up time was 95 months, and 25 patients died during the study period. The 1-year, 3-year and 5-year survival rates were 74.6% (95%CI 63.8%-85.4%), 67.4% (95%CI 55.6%-79.2%) and 55.1% (95%CI 47.9%-62.3%), respectively. The log-rank univariate analysis showed that the patients had age>40 years (P=0.042), preoperative weight loss>5 kg (P=0.002), preoperative albumin < 30 g/L (P < 0.001), paraneoplastic pemphigus complicated with bronchiolitis obliterans (P=0.002), and perioperative fungal infection (P < 0.001) had increased mortality. Cox univariate analysis showed that preoperative weight loss >5 kg (P=0.005), preoperative albumin < 30 g/L (P < 0.001), paraneoplastic pemphigus complicated with bronchiolitis obliterans (P=0.009), preoperative bacterial pulmonary infection (P=0.007), prolonged surgical time (P=0.048), postoperative oxygenation index (P=0.012) and low albumin (P=0.010) and hemoglobin concentration (P=0.035) in ICU, acute physiology and chronic health evaluation (APACHE Ⅱ) score (P=0.001); sequential organ failure assessment (SOFA) score (P=0.010), and postoperative fungal infection (P < 0.001) were risk factors for long-term survival. Cox regression model for multivariate analysis showed that preoperative weight loss > 5 kg (HR 4.44; 95%CI 1.47-13.38; P=0.008), and preoperative albumin < 30 g/L (HR 4.38; 95%CI 1.72-11.12; P=0.002), bronchiolitis obliterans (HR 2.69; 95%CI 1.12-6.50; P=0.027), and postoperative fungal infection (HR 4.85; 95%CI 2.01-11.72; P < 0.001) were independent risk factors for postoperative mortality. CONCLUSION: The 5-year survival rate of critically ill patients undergoing surgery for paraneoplastic pemphigus combined with solid tumors is approximately 55.1%, with preoperative weight loss > 5 kg, albumin < 30 g/L, bronchiolitis obliterans and postoperative fungal infection were associated with an increased risk of near- and long-term postoperative mortality.

[Clinical outcomes and influence factors of 435 singleton pregnancies with short cervix].

Objective: To investigate the clinical outcomes of different treatment options on singleton short cervix and its influence factors. Methods: Totally 435 cases of singleton pregnancies who were diagnosed with short cervix (≤25 mm) between 12 to 33+6 gestational weeks in Peking University First Hospital from January 2018 to December 2018 were enrolled, including 21 cases with cervical length <10 mm, 414 cases with cervical length between 10 to 25 mm. The onset time was <24 gestational weeks in 106 cases, while 104 cases were at 24-29+6 gestational weeks and 225 cases of ≥30 gestational weeks. Gestational outcomes including delivery before 37 weeks, delivery before 34 weeks, neonatal birth weight (NBW) and adverse neonatal outcome (ANO) were compared among three treatment groups: rest group, progesterone group and cerclage group. Influence factors were also investigated. Results: (1) The incidence of short cervix in pregnancy was 7.07% (435/6 155), while 106 cases were at <24 gestational weeks (1.72%, 106/6 155), 104 cases (1.69%, 104/6 155) at 24-29+6 gestational weeks and 225 cases (3.66%, 225/6 155) at ≥30 gestational weeks. (2) In the group of cervical length <10 mm, rate of delivery before 37 and 34 weeks were 62% (13/21) and 57% (12/21) respectively. One case of progesterone treatment underwent miscarriage. Compared with rest group (n=8), delivery weeks [28.5 (25.0-40.0) vs 37.0 (28.0-40.0), P=0.020] and NBW [1 245 g (630-3 830 g) vs 2 648 g (1 560-3 830 g), P=0.028] were higher in cerclage group (n=9), while ANO was not statistically different (P>0.05). (3) In the group of cervical length ≥10 mm before 24 gestational weeks, the delivery weeks, incidence of delivery before 34 weeks, adjusted incidence of delivery before 37 weeks, NBW and ANO were not statistically different (P>0.05) among rest group (n=36), progesterone group (n=26) and cerclage group (n=34). In vitro fertilization (OR=11.97, 95%CI: 1.88-76.44, P=0.009), infection (OR=46.03, 95%CI: 5.12-413.58, P=0.001), sludge on sonography (OR=9.87, 95%CI: 1.69-57.60, P=0.011) and history of short cervix (OR=7.24, 95%CI: 1.04-50.24, P=0.045) were independent risk factors of preterm birth. (4) In the group of cervical length ≥10 mm and gestational weeks between 24-29+6, the delivery weeks, incidence of delivery before 37 weeks, incidence of delivery before 34 weeks, NBW and ANO were not statistically different (P>0.05) among rest group (n=52), progesterone group (n=34) and cerclage group (n=9). Infection was an independent risk factor of preterm birth (OR=56.40, 95%CI: 4.67-680.61, P=0.002). (5) Outcomes of 223 cases were relatively good in the group of cervical length ≥10 mm beyond 30 gestational weeks. The incidence of delivery before 34 weeks was 6.3% (14/223). The delivery weeks, incidence of delivery before 37 and 34 weeks, NBW and ANO were not statistically different (P>0.05) among 3 groups. Infection (OR=10.91, 95%CI: 2.21-53.96, P=0.003) and history of preterm birth (OR=8.63, 95%CI: 1.25-59.65, P=0.029) were independent risk factors of preterm birth. Conclusions: Short cervix is a common complication of pregnancy. Cervical cerclage is related with better outcome for patients with cervical length <10 mm. Neither progesterone nor cervical cerclage improves pregnancy outcome for >10 mm cervical length patients comparing with rest. Infection, sludge, in vitro fertilization, history of short cervix and history of preterm birth are independent risk factors of preterm birth in short cervix pregnancies.

Propofol compared with sevoflurane general anaesthesia is associated with decreased delayed neurocognitive recovery in older adults.

BACKGROUND: The choice of general anaesthetics may affect postoperative cognitive outcomes. This study was designed to compare the potential impact of propofol-based vs sevoflurane-based general anaesthesia on the development of delayed neurocognitive recovery in older adults early after major cancer surgery. METHODS: Older adults (aged ≥65 and <90 yr) who were scheduled to undergo major cancer surgery (≥2 h) were randomised to receive either propofol- or sevoflurane-based general anaesthesia. Cognitive function was assessed before and 1 week after surgery with a battery of neuropsychological tests. Age- and education-matched non-surgical controls were recruited, and their cognitive functions were tested at comparable time intervals in order to adjust for learning effects from repeated tests. Delayed neurocognitive recovery was diagnosed according to the International Study of Postoperative Cognitive Dysfunction 1 definition. RESULTS: From April 1, 2015 to October 15, 2016, 392 patients were enrolled and randomised. Of these patients, 387 completed the intervention and 30-day follow-up, and 379 completed 1-week neuropsychological tests. Fifty-nine control subjects were enrolled and completed repeated neuropsychological tests. The incidence of delayed neurocognitive recovery at 1 week was significantly lower in the propofol group [14.8% (28/189)] than in the sevoflurane group [23.2% (44/190); odds ratio=0.577; 95% confidence interval, 0.342-0.975; P=0.038]. Safety outcomes did not differ between the two groups. CONCLUSIONS: When compared with sevoflurane-based general anaesthesia, propofol-based general anaesthesia might decrease the incidence of delayed neurocognitive recovery in older adults after major cancer surgery. CLINICAL TRIALS REGISTRATION: NCT02662257; Chinese Clinical Trial Registry (identifier: ChiCTR-IPR-15006209).

Preoperative vitamin D deficiency increases the risk of postoperative cognitive dysfunction: a predefined exploratory sub-analysis.

BACKGROUND: Vitamin D is important for maintaining physiological functions including cognition and its deficiency is associated with the occurrence of cognitive impairment. This study was to explore the association between preoperative vitamin D status and the occurrence of postoperative cognitive dysfunction (POCD) in elderly patients undergoing major surgery. METHODS: This was a predefined exploratory sub-analysis of one-centre data from a randomized controlled trial. In all, 123 elderly (≥ 65 years) patients who were scheduled to undergo major cancer surgery were recruited. Serum 25-hydroxyvitamin D concentration was measured before surgery. In total, 59 nonsurgical control subjects with comparable age and education level were also enrolled. A battery of neuropsychological tests was administered the day before and the 7th day after surgery in patients or at the same time interval in control subjects. POCD was diagnosed according to the ISPOCD1 definition. RESULTS: 71.5% (88/123) of elderly patients had vitamin D deficiency (serum 25-hydroxyvitamin D concentration < 12 ng/ml) before surgery; 24.4% (30/123) of them developed cognitive dysfunction at 1 week after surgery. After adjusting for confounding factors, high preoperative serum 25-hydroxyvitamine D concentration was related to a decreased risk of POCD (odds ratio [OR]: 0.829, 95% confidence interval [CI]: 0.708-0.971; P = 0.020), whereas preoperative vitamin D deficiency was associated with an increased risk of POCD (OR: 8.427, 95% CI: 1.595-44.511; P = 0.012). CONCLUSIONS: Vitamin D deficiency is prevalent in elderly patients undergoing major cancer surgery and increases the risk of early POCD development. Whether prophylactic vitamin D supplementation can reduce POCD in the elderly deserves further study.

Manipulation of group-velocity-locked vector dissipative solitons and properties of the generated high-order vector soliton structure.

Details of various composites of the projections originated from a fundamental group-velocity-locked vector dissipative soliton (GVLVDS) are both experimentally and numerically explored. By combining the projections from the orthogonal polarization components of the GVLVDS, a high-order vector soliton structure with a double-humped pulse profile along one polarization and a single-humped pulse profile along the orthogonal polarization can be observed. Moreover, by de-chirping the composite double-humped pulse, the time separation between the two humps is reduced from 15.36 ps to 1.28 ps, indicating that the frequency chirp of the GVLVDS contributes significantly to the shaping of the double-humped pulse profile.

[Risk factors of postoperative complications after laparoscopic surgery for pheochromocytoma].

Objective: To investigate the effects of intraoperative hemodynamic instability on postoperative complications of laparoscopic surgery for pheochromocytoma. Methods: It was a retrospective cohort study. According to inclusion/exclusion criteria, adult patients underwent laparoscopic surgery for pheochromocytoma from January 2005 to December 2017 in Peking University First Hospital were enrolled in this study. Eligible patients were divided into two groups by evidence of postoperative complications to find out the effects of intraoperative hemodynamic instability and its' effects on other prognostic indices. The normally distributed continuous variables were compared between two groups by Student's t test, Mann-Whitney U test were used for the comparison for non-normally distributed continuous variables and χ(2) test for categorical variables. Results: A total of 198 patients were finally enrolled in this study, including 87 males and 111 females with an average age of (47±15) years. Postoperative complications occurred in 17 patients with an incidence of 8.6%, and intraoperative hemodynamic instability occurred in 45 patients (22.7%). It was found that history of stroke[odds ratio (OR)=13.387, 95% confidence interval (CI): 2.284-78.460, P=0.004], intraoperative hemodynamic instability (OR=3.351, 95%CI: 1.119-10.039, P=0.031) and intraoperative positive fluid balance (for each additional 100 ml) (OR=1.087, 95%CI: 1.031-1.146, P=0.002)were the independent risk factors of postoperative complications of laparoscopic surgery for pheochromocytoma. Furthermore, more postoperative complications, higher rate of admitting to ICU and longer hospital stay was found in patients with hemodynamic instability. Conclusion: Intraoperative hemodynamic instability is an independent risk factor for postoperative complications of laparoscopic surgery in patients with pheochromocytoma, and it associates with more postoperative complications and higher rate of admitting to ICU.

[Analysis of neoadjuvant docetaxel, carboplatin and trastuzumab (TCH) in HER-2-positive breast cancer].

Objective: To analyze docetaxel (T) and carboplatin (C) combined with trastuzumab (H) -TCH regimen as neoadjuvant systemic therapy in early breast cancer patients with human epidermal growth factor receptor 2 (HER-2) positive. Methods: From January 2008 to December 2014, the data of patients diagnosed as early breast cancer in Breast Disease Center of Peking University First Hospital were retrospective reviewed. The data of patients with HER-2 positive conducted TCH neoadjuvant therapy and surgery, and with the complete clinicopathological information were analyzed. Results: A total of 77 cases were enrolled in this study. We defined G2+ G3+ G4+ G5 as responsive group according to Miller-Payne grading system, the responsive rate was 84.4% (65/77). The rate of complete pathological remission (pCR) was 39.0% (30/77). The 5-year disease free survival (DFS) was 87.3%, and 5-year overall survival (OS) was 93.6%. There was a significant difference between DFS and OS in the responsive group and non-responsive group (DFS: χ2=6.762, P=0.009; OS: χ2=5.062, P=0.024). Conclusion: TCH is an effective neoadjuvant therapy for patients with HER-2 positive breast cancer, and the toxic and side effects were under control.

[Dynamic investigation of nutritional risk in patients with malignant tumor during hospitalization].

Objective: To prospectively investigate the changes in nutritional status of patients with malignant tumors during hospitalization by using nutritional risk screening (NRS2002), and to analyze the correlation between the nutritional status and clinical outcomes . Methods: This was a prospective and parallel research done by multi-center collaboration from 34 hospitals in China from June to September 2014.Hospitalized patients with malignant tumors inthese departments (Department of Gastroenterology, respiratory medicine, oncology, general surgery, thoracic surgery and geriatrics)were investigated. Only the patients with age≥ 18 years and hospitalization time between 7-30 days were included. During hospitalization, the physical indexes of human bodywere measured, and the NRS 2002 scores, and monitored the nutritional support at the time points of admission and 24 hours before discharge were recorded.And whether there was a nutritional risk in hospitalized patients and its association with clinical outcomes were investigated. Results: A total of 2 402 patients with malignancies were enrolled in this study. Seventy fourpatients who did not complete NRS2002 were eliminated, and 2 328 patients were included. The number of the main diseases was the top five, including 587 cases of colorectal cancer, 567 cases of lung cancer, 564 cases of gastric cancer, 146 cases of esophageal cancer, and 119 cases of liver tumor. At the time of discharge, compared with admission, the BMI, body weight, grip and calf circumferences of patients with malignant tumor were significantly decreased (P<0.05). The total protein, albumin, prealbumin and hemoglobin were significantly lower than those at admission (P<0.05). In 2 328 patients who were completed nutritional risk screening, the rate of malnutrition at admission was 11.1% (BMI =18.5, 258/2 328) and the rate of malnutrition at discharge was 10.9% (BMI =18.5, 254/2 328), there were no significant differences (χ(2)=0.019 7, P=0.888). There were 1 204 patients with nutritional risk at admission (51.7%, NRS2002 score≥3)and 1 352 patients with nutritional risk at discharge (58.1%, NRS2002 score≥3), with significant differences (χ(2)=49.9, P<0.001). The incidence of nutritional risk in patients with colorectal, stomach, and lung tumors at discharge was significantly higher than that at admission (P<0.05). The infective complications and other complications of patients with nutritional risk were significantly greater than those without nutritional risk at admission and at discharge.ICU hospitalization stay of patients with nutritional risk was increased significantly than those without nutritional risk at admission(P=0.042). Hospitalization expenses of patients with nutritional risk was increased significantly than those of patients without nutritional risk at discharge(P<0.01). Conclusion: The patients with malignant tumor have a higher incidence rate of malnutrition at both admission and discharge and malnutritionhas correlation with adverse clinical outcomes.The aboveindicators did not improve significantly at discharge.Doctors should pay more attention to the nutritional status (screening and evaluation)of patients before discharge and use appropriate and adequate nutrition support in order to prevent the weight loss and improve the life quality of patients.

Multiple generations of high-order orbital angular momentum modes through cascaded third-harmonic generation in a 2D nonlinear photonic crystal.

We experimentally demonstrate multiple generations of high-order orbital angular momentum (OAM) modes through third-harmonic generation in a 2D nonlinear photonic crystal. Such third-harmonic generation process is achieved by cascading second-harmonic generation and sum-frequency generation using the non-collinear quasi-phase-matching technique. This technique allows multiple OAM modes with different colors to be simultaneously generated. Moreover, the OAM conservation law guarantees that the topological charge is tripled in the cascaded third-harmonic generation process. Our method is effective for obtaining multiple high-order OAM modes for optical imaging, manipulation, and communications.

[Efficacy of transforaminal endoscopic nerve root decompression in the treatment of degenerative lumbar spinal stenosis].

OBJECTIVE: To evaluate the feasibility of transforaminal endoscopic nerve root decompression for degenerative lumbar spinal stenosis (DLSS). METHODS: From July 2011 to April 2016, 96 cases of single segment DLSS were involved. All the patients had unilateral lower extremity neurological symptoms, signs, neurogenic intermittent claudication of less than 500 m. Imaging examinations (CT or MRI) or diagnostic nerve root block confirmed single segment degeneration. The mean age was (71.6±5.4) years, male: 55 cases, female: 41 cases. Their intraoperative blood loss, operation time, complications, ambulation time and discharge time were recorded. Leg pain VAS, ODI were used to evaluate the pain and lumbar function of the patients. The clinical efficacy was evaluated by Nakai evaluation. RESULTS: All the patients were performed endoscopic decompression of the lateral recess and nerve root by removing the ventral part of the superior facet joint, the ligamentum flavum and the intervertebral disc. The decompression range was from the inferior edge of the upper pedicle to the superior edge of the lower pedicle. The nerve root was detected to have no compression and the pulse of nerve root returned to normal. The patient got ambulant on the operation day and discharged if he had no discomfort symptom. In the study, 68 cases got follow up. The mean follow-up time was 12.1 months (6-63 months). The VAS at different follow-up time points was improved relative to the baseline, and the difference was statistically significant (F=491.60, P<0.001). The ODI at different follow-up time points was improved relative to the baseline, and the difference was statistically significant (F=189.91, P<0.001). The excellent and good rates of Nakai evaluation were 79.4% (excellent in 42 cases, good in 12 cases, fair in 10 cases and poor in 4 cases). The mean intraoperative blood loss was (49.29±11.86) mL. The mean operation time was (92.46±21.34) min. The mean ambulation time was 1.8 h. The mean discharge time was 2.3 days. Postoperative epidural hematoma was found in 1 case. Foot drop was found in 1 case. Second stage open surgery was performed in 6 cases. CONCLUSION: We can apply transforaminal endoscopic decompression for the patients of lumbar spinal stenosis who have unilateral nerve root irritation. Patients with transforaminal endoscopic decompression can get less surgical trauma, quick recovery and obtain good short-term outcome.

[Changes in nutritional status of patients with different diseases during hospitalization].

Objective: To evaluate changes in nutritional status of hospitalized patients with different diseases by subjective global assessment (SGA) and nutritional risk screening (NRS-2002). Methods: A prospective and parallel research done by multi-center collaboration from 34 hospitals in China from June to September 2014. Hospitalized patients with the following diseases were investigated: malignant tumor (2 487 cases), benign disease of the digestive system (1 358 cases), benign disease of the nervous system (1 043 cases), benign bone disease (451 cases), benign disease of the respiratory system(395 cases), cardiovascular disease (227 cases), benign thyroid and breast disease (179 cases), and endocrine disease (149 cases). Patients above the age of 18 and hospitalization time between 7-30 days were included. Physical indexes were measured, the NRS-2002 and SGA scores were recorded, the nutritional support were recorded during hospitalization and 24 hours after discharge from hospital. Measurement data between groups were analyzed using t test or Wilcoxon rank sum test, enumeration data and ranked data between groups were analyzed using chi-square test or Fisher exact test. Results: There were 6 638 cases of hospitalized patients, 3 861 cases were males and 2 777 were females, the male/female ratio was 1.4∶1.0; the median age was 60 years; the median height was 1.66 m; the median weight was 62 kg; the median body mass index (BMI)was 22.89 kg/m(2). At discharge, compared with that of admission, the body weight, BMI, grip strength, upper arm and calf circumferences of patients with malignant tumor were significantly decreased (t=20.15-259.67, all P<0.01); the body weight and calf circumference were significantly decreased (t=35.27, 60.40, P<0.01)of patients with digestive benign disease; the body weight of patients with benign bone diseases was decreased (t=2.12, P=0.033); the body weight, grip strength and upper arm circumference were decreased in patients with benign thyroid and breast disease (t=2.79-10.18, all P<0.01); nutritional risk incidence rate (from NRS-2002) of patients with malignant tumor was significantly higher(χ(2)=21.275, P=0.000); moderate malnutrition (from SGA) incidence rate was significantly higher(χ(2)=62.318, P=0.000; χ(2)=11.312, P<0.01) in patients with malignant tumor and with orthopedics diseases. Compared with that of admission, records of the patients with other diseases had no statistically difference at discharge, no more than 50% of the patients under risk of nutritional deficiency(except those with digestive benign diseases )received nutritional support, while the proportion of non-parenteral nutrition application was higher. Conclusion: The patients with malignant tumor have higher incidence rate of malnutrition on admission and at discharge. Doctors should pay more attention to the nutritional status(screening and evaluation) of patients before discharge and use appropriate and adequate nutrition support in order to prevent the weight loss and improve the life quality of patients.

Scheme for generating distillation-favorable continuous-variable entanglement via three concurrent parametric down-conversions in a single χ(2) nonlinear photonic crystal.

We propose to generate a single-mode-squeezing two-mode squeezed vacuum state via a single χ(2) nonlinear photonic crystal. The state is favorable for existing Gaussian entanglement distillation schemes, since local squeezing operations can enhance the final entanglement and the success probability. The crystal is designed for enabling three concurrent quasi-phase-matching parametric-down conversions, and hence relieves the auxiliary on-line bi-side local squeezing operations. The compact source opens up a way for continuous-variable quantum technologies and could find more potential applications in future large-scale quantum networks.

Coupled orbital angular momentum conversions in a quasi-periodically poled LiTaO3 crystal.

We experimentally demonstrate the orbital angular momentum (OAM) conversion by the coupled nonlinear optical processes in a quasi-periodically poled LiTaO3 crystal. In such a crystal, third-harmonic generation (THG) is realized by the coupled second-harmonic generation (SHG) and sum-frequency generation (SFG) processes, i.e., SHG is dependent on SFG and vice versa. The OAMs of the interacting waves are proved to be conserved in such coupled nonlinear optical processes. As we increase the input OAM in the experiment, the conversion efficiency decreases because of the reduced fundamental power density. Our results provide better understanding for the OAM conversions, which can be used to efficiently produce an optical OAM state at a short wavelength.

Simultaneous directional emissions of multiple quantum emitters with cross plasmonic antenna.

We introduce a cross plasmonic antenna (CPA) for the system of multiple quantum emitters (QEs) with different emission wavelengths, where the excitation light scattering and emission fluorescence of different QEs are spatially separated in four different directions. By considering the CPA as oscillating dipoles, this phenomenon is attributed to the phase differences between them. The enhancement for QEs are very strong in correponding directions. In addition, the fluorescence is strongly polarized. By adding a silver plate as substrate, the directivity can be further tuned in the whole upper half space. Our result shows that the CPA is promising for realization of an efficient, directional and strongly polarized nano-scale light source, which will have potential application in Nano-Optics.

Orbital angular momentum entanglement via fork-poling nonlinear photonic crystals.

We report a compact scheme for the generation and manipulation of photon pairs entangled in the orbital angular momentum (OAM) from the fork-poling quadratic nonlinear crystal. The χ(2)-modulation in this crystal is designed for fulfilling a tilted quasi-phase-matching geometry to ensure the efficient generation of entangled photons as well as for transferring of topological charge of the crystal to the photon pairs. Numerical results show that the OAM of photon pair is anti-correlated and the degree of OAM entanglement can be enhanced by modulating the topological charge of crystal, which indicates a feasible extension to high-dimensional OAM entanglement. These studies suggest that the fork-poling nonlinear photonic crystal a unique platform for compact generation and manipulation of high-dimensional and high-order OAM entanglement, which may have potential applications in quantum communication, quantum cryptography and quantum remote sensing.

Refractive index sensor based on the leaky radiation of a microfiber.

In this work we present a refractive index sensor based on the leaky radiation of a microfiber. The 5.3um diameter microfiber is fabricated by drawing a commercial optical fiber. When the microfiber is immersed into a liquid with larger refractive index than the effective index of fiber mode, the light will leak out through the leaky radiation process. The variation of refractive index of liquid can be monitored by measuring radiation angle of light. The refractive index sensitivity can be over 400 degree/RIU in theory. In the experiment, the variation value 0.001 of refractive index of liquid around this microfiber can be detected through this technique. This work provides a simple and sensitive method for refractive index sensing application.

Concurrent optical parametric down-conversion in χ(2) nonlinear photonic crystals.

We experimentally investigated concurrent parametric downconversion processes in a two-dimensional hexagonally poled lithium tantalate crystal. The substantial enhancement of parametric gain was observed when concurrent processes shared a common parametric beam. Both degenerate and nondegenerate concurrent parametric downconversion processes were studied. Analyses of the spatial forms and output angles showed a strong dependence on the working temperature, during which a well-defined beamlike parametric output was observed. Our results will stimulate the design for coherent high-gain generation of multiple parametric beams and also shed light on the compact engineering of path-entanglement with specific spatial forms based on concurrent spontaneous parametric downconversion processes.

Mode division multiplexing in a polymer-loaded plasmonic planar waveguide.

A mode division multiplexer (MDM) based on in-plane diffractions is experimentally demonstrated in a polymer-loaded plasmonic planar waveguide. Three guided modes (TM1, TE1, and TM2) were well demultiplexed by a focusing design with a focal length of about 40 µm, which are clearly distinguished by the polarization control. The experimental results well reproduced the theoretical design and calculation. Moreover, the demultiplexed focal spots directly reflect the different modes, by which a mode diagram of the dielectric-loaded planar waveguide was vividly mapped out by varying the polymer layer thickness. In this regard, the proposed device may not only serve as a MDM for the integrated optics but can also provide a new strategy in analyzing the guided modes.

Diode-pumped 1988-nm Tm:YAP laser mode-locked by intracavity second-harmonic generation in periodically poled LiNbO3.

We report a diode-pumped intracavity second-harmonic generation mode-locked solid-state Tm:YAP laser operating at 1988 nm using a periodically poled congruent LiNbO3 as the nonlinear crystal. The threshold of continuous wave mode locking is 11.6 W. The maximum output power is 1.67 W, while the shortest pulse obtained is 4.7 ps at a repetition rate of 97.09 MHz.