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1.
Qual Life Res ; 32(9): 2477-2487, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37031427

RESUMO

PURPOSE: The European Organisation for Research and Treatment of Cancer (EORTC) quality of life core questionnaire (QLQ-C30) is a validated and widely-used Patient-Reported Outcome Measure for measuring the health-related quality of life (HRQoL) of cancer patients. To facilitate interpretation of results obtained in studies using the EORTC QLQ-C30, we generated normative data for the Dutch general population, stratified by age and sex. METHODS: Dutch participants were selected from a larger cross-sectional online panel research study collecting EORTC QLQ-C30 general population normative data across 15 countries. EORTC QLQ-C30 raw scores based on a 4-point response scale were transformed to linear scores ranging from 0 to 100. Transformed scores were weighted based on the United Nations population distribution statistics and presented by age and sex/age. Differences in scale scores of ≥ 10 points in HRQoL were applied to indicate clinical relevance. RESULTS: One thousand respondents completed the online survey. Stratified by age, clinically meaningful differences were observed, with worse physical functioning scores and better emotional functioning scores with increased age. Symptom scores remained stable across age groups, except for small age differences observed for fatigue, nausea/vomiting, diarrhoea, and financial difficulties. Stratified by sex/age, men generally scored better for both functioning and symptoms. However, these differences were not clinically meaningful. CONCLUSIONS: These updated normative EORTC QLQ-C30 for the Dutch general population can be used to better interpret HRQoL data obtained from Dutch cancer patients. Being part of a larger international study, these data can further be used for inter-country comparisons in multi-national studies.


Assuntos
Neoplasias , Qualidade de Vida , Masculino , Humanos , Qualidade de Vida/psicologia , Estudos Transversais , Neoplasias/terapia , Inquéritos e Questionários , Etnicidade
2.
HNO ; 71(12): 795-801, 2023 Dec.
Artigo em Alemão | MEDLINE | ID: mdl-37707515

RESUMO

BACKGROUND: Persistent complex defects and dysfunctions of the upper aerodigestive tract after tumor surgery represent a major challenge. The aim of this study was to evaluate the effectiveness of an interdisciplinary approach using the free anterolateral thigh flap (ALT) as a reconstruction option in the upper aerodigestive tract. MATERIALS AND METHODS: The retrospective study identified 5 patients with complex defects after laryngectomy/pharyngolaryngectomy (LE/PLE) and multiple revision surgeries between 2017 and 2023. The operations were performed by an interdisciplinary team from otolaryngology, plastic surgery, and visceral/thoracic surgery. The results of the microsurgical reconstruction were analyzed. RESULTS: There was an average of six previous operations. The defects included tracheoesophageal fistulas, pharyngocutaneous fistulas, neopharyngeal stenosis, and combinations thereof. Successful reconstruction was achieved in 100% of patients using the ALT flap. In 2 patients, ALT flow-through flaps were used with an additional free jejunal interposition (JI) and in 3 patients split-ALT flaps were used. The major complication rate was 40% and the minor complication rate was 20%. CONCLUSION: Complex defects of the upper aerodigestive tract with multiple previous operations can be successfully reconstructed. Because of its versatility, the ALT flap seems to be a very good option. Prerequisite for this is an interdisciplinary treatment approach with a critical assessment of patient- and disease-specific factors.


Assuntos
Fístula Cutânea , Retalhos de Tecido Biológico , Procedimentos de Cirurgia Plástica , Humanos , Estudos Retrospectivos , Algoritmos
3.
Appl Opt ; 60(19): D43-D51, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34263827

RESUMO

We present the inscription of narrow-linewidth fiber Bragg gratings (FBGs) into different types of multicore fibers (MCFs) using ultrashort laser pulses and the phase mask technique, which can act as notch filters. Such filters are required, e.g., to suppress light emitted by hydroxyl in the Earth's upper atmosphere, which disturbs ground-based observation of extraterrestrial objects in the near infrared. However, the inscription into a commercially available seven-core fiber showed a quite large core-to-core deviation of the resonance wavelength of up to 0.45 nm. Two options are presented to overcome this: first, we present the photo-treatment of the FBGs to tune the resonance wavelength, which allows for sufficient resonance shifts. Second, adapted MCFs containing 12 cores, arranged on a circle, are fabricated. For this, two different fabrication procedures were investigated, namely, the mechanical drilling of the preform for a rod-in-tube version as well as a stack-and-draw approach. Both adapted MCFs yielded significant improvements with core-to-core wavelength variations of the FBGs of only about 0.18 nm and 0.11 nm, respectively, sufficient to fulfill the requirements for astronomical filter applications as discussed above.

4.
Opt Express ; 28(24): 35682-35694, 2020 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-33379679

RESUMO

We present an innovative concept of a semi-aperiodic phase mask design that enables the realization of multi-notch fiber Bragg gratings (FBG). This design utilizes the overlap and interference of near-infrared ultrashort laser pulses diffracted by short sequenced phase mask sections, which not only allows for a highly stable and reproducible inscription of a large number of wavelength filters but also paves the way towards full aperiodic phase masks. The semi-aperiodic FBG inscribed by this phase mask enables versatile notch filters showing multiple non-equidistant resonances. Those filters target applications, for instance in ground-based telescopes, where a large number of hydroxyl emission lines emitted in the upper atmosphere at near-infrared wavelengths restrict the observation of faint extraterrestrial objects.

5.
Nat Mater ; 16(4): 433-438, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27918567

RESUMO

Parity-time (PT)-symmetric crystals are a class of non-Hermitian systems that allow, for example, the existence of modes with real propagation constants, for self-orthogonality of propagating modes, and for uni-directional invisibility at defects. Photonic PT-symmetric systems that also support topological states could be useful for shaping and routing light waves. However, it is currently debated whether topological interface states can exist at all in PT-symmetric systems. Here, we show theoretically and demonstrate experimentally the existence of such states: states that are localized at the interface between two topologically distinct PT-symmetric photonic lattices. We find analytical closed form solutions of topological PT-symmetric interface states, and observe them through fluorescence microscopy in a passive PT-symmetric dimerized photonic lattice. Our results are relevant towards approaches to localize light on the interface between non-Hermitian crystals.

6.
Opt Express ; 26(18): 24089-24097, 2018 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-30184901

RESUMO

Direct writing of single-mode waveguides into crystalline silicon using ps laser pulses is presented. The embedded structures were fabricated by moving the focal position along the beam axis with the help of a long distance microscope objective. In situ monitoring during inscription was performed to analyze the processing dynamics. The waveguide generation is based on pronounced multi-pulse interaction at moderate pulse energies around 100 nJ. All samples were characterized in terms of mode field distribution and damping losses. Calculations indicate an induced refractive index change in the range of 10-3 to 10-2. Moreover, a Y-splitter was realized to demonstrate the potential of this process.

7.
Opt Lett ; 43(24): 6069-6072, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30548006

RESUMO

Diffraction gratings are transversally inscribed in the bulk of monolithic crystalline silicon with infrared nanosecond laser pulses. Nanoscale material analyses of the modifications composing the gratings show that they rely on laser-induced stress associated with a positive refractive index change as confirmed with phase-shift interferometry. Characterizations of the optical properties of the gratings, including the diffraction angles and the efficiency of the different orders, are carried out. The refractive index change obtained from these measurements is in good agreement with the phase-shift measurements. Finally, we show that the grating diffraction efficiency depends strongly on the laser writing speed.

8.
Appl Opt ; 57(16): 4618-4632, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29877371

RESUMO

Ultrashort laser pulses allow for the in-volume processing of glass through non-linear absorption, resulting in permanent material changes and the generation of internal stress. Across the manifold potential applications of this technology, process optimization requires a detailed understanding of the laser-matter interaction. Of particular relevance are the deposition of energy inside the material and the subsequent relaxation processes. In this paper, we investigate the spatio-temporal evolution of free carriers, energy transfer, and the resulting permanent modifications in the volume of glass during and after exposure to femtosecond and picosecond pulses. For this purpose, we employ time-resolved microscopy in order to obtain shadowgraphic and interferometric images that allow relating the transient distributions to the refractive index change profile. Whereas the plasma generation time is given by the pulse duration, the thermal dynamics occur over several microseconds. Among the most notable features is the emergence of a pressure wave due to the sudden increase of temperature and pressure within the interaction volume. We show how the structure of the modifications, including material disruptions as well as local defects, can be directly influenced by a judicious choice of pulse duration, pulse energy, and focus geometry.

9.
Br J Cancer ; 116(2): 253-259, 2017 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-27898656

RESUMO

BACKGROUND: The rate of interval cancers is an established indicator for the performance of a cancer-screening programme. METHODS: We examined the incidence, tumour characteristics and risk factors of melanoma interval cancers that occurred in participants of the SCREEN project, which was carried out 2003/2004 in Schleswig-Holstein, Germany. Data from 350 306 SCREEN participants, who had been screened negative for melanoma, were linked to data of the state cancer registry. Melanoma interval cancers were defined as melanomas diagnosed within 4-24 months after SCREEN examination. Results were compared with melanomas of the pre-SCREEN era (1999-2002), extracted from the cancer registry. RESULTS: The overall relative incidence of melanoma interval cancers in terms of observed/expected ratio was 0.93 (95% CI: 0.82-1.05; in situ: 1.61 (1.32-1.95), invasive: 0.71 (0.60-0.84)). Compared with melanomas of the pre-SCREEN era, the interval melanomas were thinner and had a slightly greater proportion of lentigo maligna melanomas whereas nodular melanomas were less frequent. INTERPRETATION: The results indicate a moderate performance of the SCREEN intervention with an excess of in situ melanomas. In part, the findings might be due to specifics of the SCREEN project, in particular a short-term follow-up of patients at high risk for melanoma.


Assuntos
Programas de Rastreamento , Melanoma , Neoplasias Cutâneas , Adulto , Idoso , Idoso de 80 Anos ou mais , Detecção Precoce de Câncer/métodos , Detecção Precoce de Câncer/normas , Feminino , Alemanha/epidemiologia , Humanos , Incidência , Masculino , Programas de Rastreamento/métodos , Programas de Rastreamento/normas , Melanoma/diagnóstico , Melanoma/epidemiologia , Melanoma/patologia , Pessoa de Meia-Idade , Sistema de Registros , Fatores de Risco , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/epidemiologia , Neoplasias Cutâneas/patologia , Fatores de Tempo , Adulto Jovem
10.
Qual Life Res ; 26(5): 1105-1117, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-27830512

RESUMO

PURPOSE: Recently, we developed a computer-adaptive test (CAT) for assessing health-related quality of life (HRQoL) in children and adolescents: the Kids-CAT. It measures five generic HRQoL dimensions. The aims of this article were (1) to present the study design and (2) to investigate its psychometric properties in a clinical setting. METHODS: The Kids-CAT study is a longitudinal prospective study with eight measurements over one year at two University Medical Centers in Germany. For validating the Kids-CAT, 270 consecutive 7- to 17-year-old patients with asthma (n = 52), diabetes (n = 182) or juvenile arthritis (n = 36) answered well-established HRQoL instruments (Pediatric Quality of Life Inventory™ (PedsQL), KIDSCREEN-27) and scales measuring related constructs (e.g., social support, self-efficacy). Measurement precision, test-retest reliability, convergent and discriminant validity were investigated. RESULTS: The mean standard error of measurement ranged between .38 and .49 for the five dimensions, which equals a reliability between .86 and .76, respectively. The Kids-CAT measured most reliably in the lower HRQoL range. Convergent validity was supported by moderate to high correlations of the Kids-CAT dimensions with corresponding PedsQL dimensions ranging between .52 and .72. A lower correlation was found between the social dimensions of both instruments. Discriminant validity was confirmed by lower correlations with non-corresponding subscales of the PedsQL. CONCLUSIONS: The Kids-CAT measures pediatric HRQoL reliably, particularly in lower areas of HRQoL. Its test-retest reliability should be re-investigated in future studies. The validity of the instrument was demonstrated. Overall, results suggest that the Kids-CAT is a promising candidate for detecting psychosocial needs in chronically ill children.


Assuntos
Computadores/estatística & dados numéricos , Psicometria/métodos , Perfil de Impacto da Doença , Adolescente , Criança , Feminino , Humanos , Estudos Longitudinais , Masculino , Estudos Prospectivos , Projetos de Pesquisa , Inquéritos e Questionários
11.
Qual Life Res ; 25(6): 1339-47, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26353906

RESUMO

OBJECTIVE: Significant life events such as severe health status changes or intensive medical treatment often trigger response shifts in individuals that may hamper the comparison of measurements over time. Drawing from the Oort model, this study aims at detecting response shift at the item level in psychosomatic inpatients and evaluating its impact on the validity of comparing repeated measurements. STUDY DESIGN AND SETTING: Complete pretest and posttest data were available from 1188 patients who had filled out the ICD-10 Symptom Rating (ISR) scale at admission and discharge, on average 24 days after intake. Reconceptualization, reprioritization, and recalibration response shifts were explored applying tests of measurement invariance. In the item-level approach, all model parameters were constrained to be equal between pretest and posttest. If non-invariance was detected, these were linked to the different types of response shift. RESULTS: When constraining across-occasion model parameters, model fit worsened as indicated by a significant Satorra-Bentler Chi-square difference test suggesting potential presence of response shifts. A close examination revealed presence of two types of response shift, i.e., (non)uniform recalibration and both higher- and lower-level reconceptualization response shifts leading to four model adjustments. CONCLUSIONS: Our analyses suggest that psychosomatic inpatients experienced some response shifts during their hospital stay. According to the hierarchy of measurement invariance, however, only one of the detected non-invariances is critical for unbiased mean comparisons over time, which did not have a substantial impact on estimating change. Hence, the use of the ISR can be recommended for outcomes assessment in clinical routine, as change score estimates do not seem hampered by response shift effects.


Assuntos
Nível de Saúde , Pacientes Internados/psicologia , Transtornos Psicofisiológicos/psicologia , Qualidade de Vida/psicologia , Perfil de Impacto da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Reprodutibilidade dos Testes , Fatores de Tempo
12.
Qual Life Res ; 25(3): 585-94, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26790429

RESUMO

PURPOSE: To describe the implementation process of a computer-adaptive test (CAT) for measuring health-related quality of life (HRQoL) of children and adolescents in two pediatric clinics in Germany. The study focuses on the feasibility and user experience with the Kids-CAT, particularly the patients' experience with the tool and the pediatricians' experience with the Kids-CAT Report. METHODS: The Kids-CAT was completed by 312 children and adolescents with asthma, diabetes or rheumatoid arthritis. The test was applied during four clinical visits over a 1-year period. A feedback report with the test results was made available to the pediatricians. To assess both feasibility and acceptability, a multimethod research design was used. To assess the patients' experience with the tool, the children and adolescents completed a questionnaire. To assess the clinicians' experience, two focus groups were conducted with eight pediatricians. RESULTS: The children and adolescents indicated that the Kids-CAT was easy to complete. All pediatricians reported that the Kids-CAT was straightforward and easy to understand and integrate into clinical practice; they also expressed that routine implementation of the tool would be desirable and that the report was a valuable source of information, facilitating the assessment of self-reported HRQoL of their patients. CONCLUSIONS: The Kids-CAT was considered an efficient and valuable tool for assessing HRQoL in children and adolescents. The Kids-CAT Report promises to be a useful adjunct to standard clinical care with the potential to improve patient-physician communication, enabling pediatricians to evaluate and monitor their young patients' self-reported HRQoL.


Assuntos
Indicadores Básicos de Saúde , Aplicações da Informática Médica , Avaliação de Resultados da Assistência ao Paciente , Qualidade de Vida , Autorrelato , Adolescente , Atitude do Pessoal de Saúde , Criança , Computadores , Estudos de Viabilidade , Feminino , Grupos Focais , Alemanha , Humanos , Masculino , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Relações Médico-Paciente , Estudos Prospectivos , Inquéritos e Questionários
13.
HNO ; 64(7): 508-14, 2016 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-26403994

RESUMO

During the past three decades, the use of voice prostheses has developed worldwide into the gold standard for voice rehabilitation after total laryngectomy. Insertion of a voice prosthesis is a simple and rapid surgical procedure, which is associated with a low rate of complications. The current article describes the cases of 2 patients showing a rapid development of granulation tissue around the voice fistula, leading to complete incarceration of the prosthesis and subtotal/total stenosis of the neopharynx.


Assuntos
Laringectomia/efeitos adversos , Laringectomia/reabilitação , Laringe Artificial/efeitos adversos , Doenças Raras/terapia , Fístula Traqueoesofágica/etiologia , Fístula Traqueoesofágica/cirurgia , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Raras/etiologia , Resultado do Tratamento , Distúrbios da Voz/etiologia , Distúrbios da Voz/reabilitação
14.
Opt Express ; 23(16): 21392-402, 2015 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-26367987

RESUMO

The fabrication of arrayed waveguide gratings (AWGs) using the femtosecond laser direct-write technique is investigated. We successfully demonstrate the fabrication of large planar waveguides that act as 2D free propagation zones. These slabs were found to have a highly uniform refractive index with a standard deviation of 1.97% relative to the total index contrast. The incorporation of low loss linear adiabatic tapers resulted in an increase of transmission by 90%. Strategies for manufacturing integrated laser written AWGs using continuous contouring to avoid lossy defects are discussed and demonstrated.

15.
Qual Life Res ; 24(4): 871-84, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25307509

RESUMO

PURPOSE: Assessing health-related quality of life (HRQoL) via Computerized Adaptive Tests (CAT) provides greater measurement precision coupled with a lower test burden compared to conventional tests. Currently, there are no European pediatric HRQoL CATs available. This manuscript aims at describing the development of a HRQoL CAT for children and adolescents: the Kids-CAT, which was developed based on the established KIDSCREEN-27 HRQoL domain structure. METHODS: The Kids-CAT was developed combining classical test theory and item response theory methods and using large archival data of European KIDSCREEN norm studies (n = 10,577-19,580). Methods were applied in line with the US PROMIS project. Item bank development included the investigation of unidimensionality, local independence, exploration of Differential Item Functioning (DIF), evaluation of Item Response Curves (IRCs), estimation and norming of item parameters as well as first CAT simulations. RESULTS: The Kids-CAT was successfully built covering five item banks (with 26-46 items each) to measure physical well-being, psychological well-being, parent relations, social support and peers, and school well-being. The Kids-CAT item banks proved excellent psychometric properties: high content validity, unidimensionality, local independence, low DIF, and model conform IRCs. In CAT simulations, seven items were needed to achieve a measurement precision between .8 and .9 (reliability). It has a child-friendly design, is easy accessible online and gives immediate feedback reports of scores. CONCLUSIONS: The Kids-CAT has the potential to advance pediatric HRQoL measurement by making it less burdensome and enhancing the patient-doctor communication.


Assuntos
Processamento Eletrônico de Dados/métodos , Indicadores Básicos de Saúde , Nível de Saúde , Psicometria/métodos , Qualidade de Vida , Adolescente , Criança , Feminino , Humanos , Masculino , Pediatria , Psicometria/instrumentação , Reprodutibilidade dos Testes , Autorrelato , Inquéritos e Questionários
16.
Opt Lett ; 39(1): 123-6, 2014 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-24365838

RESUMO

We report the observation of near-perfect light wave transfer by emulating quantum state transfer on a lattice with Hamiltonian dynamics, i.e., time-dependent intersite couplings. The structure transferring a single waveguide excitation over 11 sites with a fidelity of 0.93 works for classical light as well as single photons. As our implementation of perfect quantum state transfer uses a photonic setting, we introduce polarization as a new degree of freedom to the transport protocol. We demonstrate rotation operations of up to 40° on polarization during state transfer.

17.
Opt Lett ; 39(24): 6831-4, 2014 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-25503008

RESUMO

In this work, we discuss the management of radiation loss in photonic waveguides. As an experimental basis, we introduce a new technique of fabricating waveguides with tunable loss, which is particularly useful when implementing non-Hermitian (PT-symmetric) systems. To this end, we employ laser-written waveguides with a transverse sinusoidal modulation, which causes well-controllable radiation losses of almost arbitrary amount. Numerical simulations support our experimental findings. Our study shows that the radiation loss not only depends on the local waveguide curvature but also is influenced by interference effects. As a consequence, the loss is a nonmonotonous function of the bending parameters, such as period length.

18.
Qual Life Res ; 23(9): 2531-43, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24777867

RESUMO

PURPOSE: To assess stable effects of self-management programs, measurement instruments should primarily capture the attributes of interest, for example, the self-management skills of the measured persons. However, measurements of psychological constructs are always influenced by both aspects of the situation (states) and aspects of the person (traits). This study tests whether the Health Education Impact Questionnaire (heiQ™), an instrument assessing a wide range of proximal outcomes of self-management programs, is primarily influenced by person factors instead of situational factors. Furthermore, measurement invariance over time, changes in traits and predictors of change for each heiQ™ scale were examined. METHODS: Subjects were N = 580 patients with rheumatism, asthma, orthopedic conditions or inflammatory bowel disease, who filled out the heiQ™ at the beginning, the end of and 3 months after a disease-specific inpatient rehabilitation program in Germany. Structural equation modeling techniques were used to estimate latent trait-change models and test for measurement invariance in each heiQ™ scale. Coefficients of consistency, occasion specificity and reliability were computed. RESULTS: All scales showed scalar invariance over time. Reliability coefficients were high (0.80-0.94), and consistency coefficients (0.49-0.79) were always substantially higher than occasion specificity coefficients (0.14-0.38), indicating that the heiQ™ scales primarily capture person factors. Trait-changes with small to medium effect sizes were shown in five scales and were affected by sex, age and diagnostic group. CONCLUSION: The heiQ™ can be used to assess stable effects in important outcomes of self-management programs over time, e.g., changes in self-management skills or emotional well-being.


Assuntos
Doença Crônica/reabilitação , Educação em Saúde , Autocuidado/métodos , Inquéritos e Questionários , Adulto , Feminino , Alemanha , Humanos , Pacientes Internados , Masculino , Pessoa de Meia-Idade , Teoria Psicológica , Psicometria , Qualidade de Vida , Reprodutibilidade dos Testes
19.
Appl Opt ; 53(13): 2886-91, 2014 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-24921876

RESUMO

We present a flexible technology to generate broadband antireflection (AR) structures for the terahertz (THz) frequency range on planar and curved surfaces of silicon optics. Ultrashort laser pulses are used to ablate the surface to form a pattern of conical pillars with a period of 30 µm. These subwavelength structures act as an effective medium with gradual transition of the refractive index from air to silicon, which reduces the Fresnel reflection losses. The characterization with the THz time-domain spectroscopy system shows an AR effect for a frequency range of 0.1-1.5 THz with a maximum enhancement of the spectral amplitude by ca. 32% at 0.4 THz for planar surfaces. In addition, we demonstrate laser-generated AR structures on convex silicon lenses of both photoconductive emitter and detector devices. Here, the THz pulse amplitude can be increased by about 28%, and single frequencies even show an improvement of the spectral amplitude up to 58%.

20.
Opt Express ; 21(14): 16431-43, 2013 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-23938494

RESUMO

In this study we present a new measurement technique to investigate the timescales of back side ablation of conductive films, using Molybdenum as an application example from photovoltaics. With ultrashort laser pulses at fluences below 0.6 J/cm(2), we ablate the Mo film in the shape of a fully intact Mo 'disc' from a transparent substrate. By monitoring the time-dependent current flow across a specifically developed test structure, we determine the time required for the lift-off of the disc. This value decreases with increasing laser fluence down to a minimum of 21 ± 2 ns. Furthermore, we record trajectories of the discs using a shadowgraphic setup. Ablated discs escape with a maximum velocity of 150 ± 5 m/s whereas droplets of Mo forming at the center of the disc can reach velocities up to 710 ± 11 m/s.


Assuntos
Condutometria/métodos , Lasers , Teste de Materiais/métodos , Membranas Artificiais , Molibdênio/química , Molibdênio/efeitos da radiação , Refratometria/métodos , Molibdênio/análise
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