Polarization-separating Alvarez metalens.

The rapid advancements in optical communication technologies have highlighted traditional optical components' limitations, particularly in size, adaptability, and integration capabilities, underscoring the need for more compact and versatile solutions. Metalenses offer a promising pathway to address these challenges, with their ability to provide high-functionality, miniaturized optical components. We developed a varifocal metalens with a polarization separation function designed for the wavelength of 1550 nm for potential application for next-generation communication technologies. To integrate the varifocal and polarization separation functions, polarization-dependent phase profiles for an off-axis Alvarez lens were derived and encoded by amorphous silicon pillar meta-atoms with rectangular cross sections to provide independent 0-2π phase delays for both orthogonal linear polarization components. The fabricated metalens achieved a varifocal range of 0.75 mm to 10.65 mm and a polarization extinction ratio of 18.5 dB.

Linear polarization-separating metalens at long-wavelength infrared.

We designed and fabricated a linear polarization-separation metalens (PSM) made of single-crystal silicon (sc-Si) for long-wavelength infrared (LWIR) imaging. The PSM comprises sc-Si dielectric waveguide pillar meta-atoms with rectangular cross-sections, providing a full 2π phase delay range for two orthogonal linear polarization components with high transmittances (>70%). Electron beam lithography and deep reactive ion etching were used to fabricate the PSM. Polarization-separation imaging of elevated and ambient temperature objects was demonstrated with high extinction ratios of 21.8 dB and 12.8 dB for the x- and y-polarizations, respectively. Additionally, polarization-sensitive imaging was demonstrated by distinguishing the surfaces of a hand and toy windows. Our work enables the visualization of invisible information in the LWIR region and has widespread applications.

Demonstration of a multicolor metasurface holographic movie based on a cinematographic approach.

This study uses a dielectric metasurface to demonstrates a multicolor holographic movie. Overlapping of multiple-wavelength images at 445 nm, 532 nm, and 633 nm was achieved by maintaining the ratio between the wavelengths and the pixel periods constant. Polarization-independent pillar waveguides made of single-crystal silicon are used as meta-atoms. A movie of the rotating earth was designed by the iterative Fourier transform algorithm and fabricated using electron beam lithography to a silicon-on-sapphire substrate. The multicolor movie consists of 20 frames was successfully reproduced at the maximum speed of 30 frames per second.

Demonstration of focal length tuning by rotational varifocal moiré metalens in an ir-A wavelength.

This paper reports an experimental demonstration of moiré metalens which shows wide focal length tunability from negative to positive by mutual angle rotation at the wavelength of 900 nm. The moiré metalens was developed using high index contrast transmitarray meta-atoms made of amorphous silicon octagonal pillars, which is designed to have polarization insensitivity and full 2π phase coverage. The fabricated moiré metalens showed focal length tunability at the ranges between ±1.73 - ±5 mm, which corresponds to the optical power ranges between ±578 - ±200 m-1 at the mutual rotation between ±90 degrees.

Metasurface holographic movie: a cinematographic approach.

Animation for a metasurface hologram was achieved using a cinematographic approach. Time-lapsed images were reconstructed using sequentially arranged metasurface hologram frames. An Au rectangular nanoaperture was adopted as a meta-atom pixel and arrayed to reproduce the phase distribution based on the help of a Pancharatnam-Berry phase. We arrayed 48 hologram frames on a 2-cm2 substrate and measured and assessed the retardation of fabricated meta-atoms to reconstruct the holographic image, successfully demonstrating the movie with a frame rate of 30 frames per second.

Endoscopic System Based on Intraoral Camera and Image Processing.

OBJECTIVE: In dentistry, dentists perform many treatments with a few visually magnified information. About deep area of root canals, it commonly relies on exploration carried out with the fingers of the dentist, because the root canal entrance is very small to be observed. In clinical practice, the intraoral camera and endoscopic systems are separate devices, and there are no sensors to capture both pictures of the whole tooth and those inside the root canal. Objective of this research is to combine the intraoral camera and endoscopic system facilitating to use clinical practice. METHODS: We propose an endoscopic system based on the thin image fiber, SOPROLIFE intraoral camera as an image sensor, and a new adaptor to connect the two parts. We observed resolution charts with 50, 25, 10, and 5 line pairs (LP)/mm patterns. The acquired images are processed to both remove fixed-pattern noise using robust principal component analysis and enhance contrast. RESULTS: The acquired images containing all LP/mm patterns were clear and showed higher contrast after processing. Visibility of the processed images is 1.7, 1.6, 2.2, and 1.9 times higher than that of the raw images for 50, 25, 10, and 5 LP/mm patterns, respectively. CONCLUSION: Our fabricated endoscopic system based on the SOPROLIFE intraoral camera could observe 50, 25, 10, and 5 LP/mm patterns. After image processing, the noise was reduced, and high-contrast images were obtained. SIGNIFICANCE: This system can be considered as a further step toward facilitating noninvasive and contactless systems in clinical practice.

Real scene capturing using spherical single-element lens camera and improved restoration algorithm for radially variant blur.

A camera module employing spherical single-element lens imaging system (SSLIS) is introduced in this study. This type of imaging system can be used in compact digital cameras or mobile phone cameras, and it provides the advantages of simple design, reduced device bulkiness, and reduced manufacturing costs. When compared with conventional camera modules, our system produces radially variant blurred images, which can be satisfactorily restored by means of a polar domain deconvolution algorithm proposed in our previous study. In this study, we demonstrate an improved version of this algorithm that enables full-field-of-view (FOV) image restoration instead of the partial FOV restoration obtained via our previous algorithm. This improvement is realized by interpolating the upper and arc-shaped boundaries of the panoramic polar image such that the ringing artifacts around the center and four boundaries of the restored Cartesian image are greatly suppressed. The effectiveness of the improved algorithm is verified by image restoration of both computer simulated images and real-world scenes captured by the spherical single lens camera module. The quality of the restored image depends on the overall sparsity of all the point spread function (PSF) block Toeplitz with circulant blocks (BTCB) matrices used to restore a radially blurred image.

Fcgamma receptor regulation of Citrobacter rodentium infection.

Citrobacter rodentium, a murine model pathogen for enteropathogenic Escherichia coli, colonizes the colon utilizing attaching and effacing lesions to adhere specifically to the surfaces of intestinal epithelial cells and cause mucosal inflammation. CD4+ T cells, B cells, and immunoglobulin G (IgG), but not secretory IgA or IgM, play a critical role in eradicating this pathogen. Consistent with the importance of IgG in C. rodentium eradication, IgG transport by the neonatal Fc receptor for IgG within the intestinal epithelium also has a critical role in the regulation of C. rodentium infection. It remains to be determined, however, whether Fcgamma receptors (FcgammaRs), the receptors for the Fc portion of IgG, regulate this bacterial infection within mucosal tissues. Therefore, we investigated the roles of FcgammaRs during C. rodentium infection. Fc receptor common gamma chain (FcRgamma)-deficient mice were more susceptible to C. rodentium-induced colitis. This occurred through decreased efficiency of FcR-mediated endocytosis and maturation of dendritic cells and consequently T-cell activation of antigen-specific T cells. Moreover, in the absence of FcgammaRs, phagocytosis by macrophages was significantly diminished. Therefore, activating FcgammaRs play an important role in defending against C. rodentium infection, indicating that the critical role played by IgG in this infection is not mediated by IgG alone but is dependent upon this class of receptors.

[Successful treatment for advanced hepatocellular carcinoma by hepatic arterial infusion of CDDP powder as second-line chemotherapy].

A 72-year-old man with type C liver cirrhosis had suffered from hepatocellular carcinoma (HCC) since April, 2001. HCC spread diffusely all over the right lobe of his liver, and the serum alpha-fetoprotein (AFP) value increased up to 42,696 ng/ml in June of 2004. He was implanted with a port-catheter system, and hepatic arterial infusion chemotherapy (HAIC) using low-dose of CDDP and 5-FU was started. However, it was not effective and after 4 months, the serum AFP level increased up to 755,030 ng/ml, ascites appeared, and gastro-esophageal varices also spread. No definite metastasis was detected, then we started to second-line chemotherapy. He was then given HAIC using CDDP powder for intraarterial use (CDDP 50 mg/m(2)/20 min, monthly). After 3 courses, the serum AFP level decreased to 9 10 ng/ml, and abdominal CT revealed that the main tumor had regressed and ascites had disappeared. After one more course, the serum AFP value decreased to 8 ng/ml and complete response was achieved on abdominal CT imaging. There was no major complication related to the chemotherapy. HAIC for advanced HCC using LFP has been reported to achieve favorable results, but no other regimens have been proved to the standard for HCC. HAIC using CDDP powder for advanced HCC may be beneficial as the second-line chemotherapy.

[Outcomes of treatment with gemcitabine for unresectable pancreatic cancer].

The efficacy and safety of gemcitabine were investigated in 16 patients with unresectable pancreatic cancer (Arm A), compared with 16 patients who received chemotherapy without gemcitabine (Arm B) and 44 patients who received best supportive care (Arm C). A gemcitabine 30 min i.v. infusion at a starting dose of 1,000 mg/m2 was administered once a week for 3 weeks with a 1 week rest. Dose reduction and cycle delay were applied because of toxicity in 62.5% of the cases in the first cycle and 31.3% in the second cycle. Hematological toxicity was observed in 81.3%, nausea/vomiting in 37.5% and fatigue in 18.8%. Clinical benefit response was observed in 25.0% in Arm A, as compared with the lower rate of 6.25% in Arm B. Response rates were comparable. The median time of outpatient treatment was 98.5 days in Arm A and 34.0 days in Arm B, respectively. The median survival time was 200 days in Arm A, 121 days in Arm B and 82.5 days in Arm C, respectively. In Arm A, the higher dose intensity showed a longer survival time. The results show that gemcitabine can be administered in outpatient clinics with dose reduction and cycle delay, and that higher dose intensity generates clinical benefit, survival advantage and prolonged outpatient treatment time.