SPIE Optics + Photonics最新文献

Neural network for image-to-image control of optical tweezers 光镊图像对图像控制的神经网络

SPIE Optics + Photonics Pub Date : 2013-07-29 DOI: 10.1117/12.559564

A. Decker, R. Anderson, K. E. Weiland, S. Wrbanek

引用次数: 1

Atmospheric turbulence simulation using liquid crystal spatial light modulators 利用液晶空间光调制器模拟大气湍流

SPIE Optics + Photonics Pub Date : 2012-11-29 DOI: 10.1117/12.620407

J. Phillips, M. Goda, Jason D. Schmidt

{"title":"Atmospheric turbulence simulation using liquid crystal spatial light modulators","authors":"J. Phillips, M. Goda, Jason D. Schmidt","doi":"10.1117/12.620407","DOIUrl":"https://doi.org/10.1117/12.620407","url":null,"abstract":"Laser systems are finding a home in many military applications - such as Space Situational Awareness, imaging and weapons systems. With an increasing focus on programs that entail atmospheric propagations, there is a need for a cost effective method of performing laboratory proof-of-concept demonstrations. The use of one SLM (single phase screen) to model atmospheric effects has been investigated previously with promising results. However, some effects cannot be captured with a single SLM. This paper focuses on the addition of a second SLM and quantifying the results. Multiple screens will allow the user to independently control the Fried parameter, the isoplanatic angle, and Rytov Variance. The research is comprised of simulation and experiment. The simulation demonstrates the ability to accurately model atmospheric effects with two phase screens. Based on the simulation, a hardware implementation was tested in the lab. The results of this research show promise, however some issues remain. This thesis describes the experimental set-up and results based on measurement of phase and intensity of the propagated field. It was noted that while analytic results are replicated in simulation, similar results in the lab were difficult to achieve.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127547090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 31

Atmospheric simulation using a liquid crystal wavefront-controlling device 用液晶波前控制装置模拟大气

SPIE Optics + Photonics Pub Date : 2012-10-03 DOI: 10.1117/12.562447

M. Brooks, M. Goda

引用次数: 9

Spectral sensitivity of the circadian system 昼夜节律系统的光谱灵敏度

SPIE Optics + Photonics Pub Date : 2010-02-26 DOI: 10.1117/12.511856

M. Figueiro, John D. Bullough, M. Rea

{"title":"Spectral sensitivity of the circadian system","authors":"M. Figueiro, John D. Bullough, M. Rea","doi":"10.1117/12.511856","DOIUrl":"https://doi.org/10.1117/12.511856","url":null,"abstract":"Light exposure regulates several circadian functions in normal humans including the sleep-wake cycle. Individuals with Alzheimer’s Disease (AD) often do not have regular patterns of activity and rest, but, rather, experience random periods of sleep and agitation during both day and night. Bright light during the day and darkness at night has been shown to consolidate activity periods during the day and rest periods at night in AD patients. The important characteristics of bright light exposure (quantity, spectrum, distribution, timing and duration) for achieving these results in AD patients is not yet understood. Recent research has shown that moderate (~18 lx at the cornea) blue (~470 nm) light is effective at suppressing melatonin in normal humans. It was hypothesized that blue light applied just before AD patients retire to their beds for the night would have a measurable impact on their behavior. A pilot study was conducted for 30 days in a senior health care facility using four individuals diagnosed with mild to moderate levels of dementia. Four AD patients were exposed to arrays of blue light from light emitting diodes (max wavelength = 470 nm) in two-hour sessions (18:00 to 20:00 hours) for 10 days. As a control, they were exposed to red light (max wavelength = 640 nm) in two-hour sessions for 10 days prior to the blue light exposure. Despite the modest sample size, exposure to blue LEDs has shown to affect sleep quality and median body temperature peak of these AD patients. Median body temperature peak was delayed by approximately 2 hours after exposure to blue LEDs compared to exposure to red LEDs and sleep quality was improved. This pilot study demonstrated that light, especially LEDs, can be an important contribution to helping AD patients regulate their circadian functions.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114686514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Generating entangled states of two ququarts using linear optical elements 利用线性光学元件产生两个夸脱的纠缠态

SPIE Optics + Photonics Pub Date : 2007-03-15 DOI: 10.1117/12.698767

S. Baek, Yoon-Ho Kim

引用次数: 9

Injection of current densities over kA/cm2 in organic thin films and investigation of charge-carrier transport mechanisms in current density region between nA/cm2 and kA/cm2 在有机薄膜中注入超过kA/cm2的电流密度，并研究nA/cm2和kA/cm2之间电流密度区域的载流子输运机制

SPIE Optics + Photonics Pub Date : 2006-12-05 DOI: 10.1117/12.682122

T. Matsushima, C. Adachi

引用次数: 1

Phosphorescent iridium(III) cored dendrimers for light-emitting displays 发光显示器用磷光铱(III)芯树状大分子

SPIE Optics + Photonics Pub Date : 2006-12-05 DOI: 10.1117/12.683380

J. Ribierre, S. Staton, P. Burn, I. Samuel

{"title":"Phosphorescent iridium(III) cored dendrimers for light-emitting displays","authors":"J. Ribierre, S. Staton, P. Burn, I. Samuel","doi":"10.1117/12.683380","DOIUrl":"https://doi.org/10.1117/12.683380","url":null,"abstract":"Solution-processable electrophosphorescent dendrimers are an emerging class of materials for highly efficient light-emitting diodes. Here, we report time-resolved photoluminescence measurements in a fac-tris(2-phenylpyridyl)iridium(III) [Ir(ppy)3]-cored dendrimer in neat film and blended into a 4,4'-bis(N-carbazolyl)biphenyl (CBP) host. Our results identify the existence of a photodegradation process that occurs in solution prior to processing, which significantly affects the photoluminescence kinetics of the films and leads to lower external quantum efficiencies of solution-processed phosphorescent dendrimer light-emitting displays. In parallel, we studied the triplet-triplet exciton annihilation processes in these materials from the photoluminescence decays measured at various excitation densities. From the values of the annihilation rates, we calculated the triplet exciton diffusion lengths and estimated the limiting current densities above which annihilation would dominate in phosphorescent dendrimer light-emitting devices. The results show that the triplet exciton diffusion length is small (<15 nm) in phosphorescent dendrimers and that exciton diffusion becomes still slower in the blends, which can be interpreted by the intermolecular spacing between the phosphorescent emitters being increased, thus reducing the annihilation rate.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"6333 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130359936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of electronic properties on the threshold behaviour of organic laser diode structures 电子特性对有机激光二极管结构阈值行为的影响

SPIE Optics + Photonics Pub Date : 2006-12-05 DOI: 10.1117/12.680733

C. Pflumm, Christian A Gärtner, C. Karnutsch, U. Lemmer

{"title":"Influence of electronic properties on the threshold behaviour of organic laser diode structures","authors":"C. Pflumm, Christian A Gärtner, C. Karnutsch, U. Lemmer","doi":"10.1117/12.680733","DOIUrl":"https://doi.org/10.1117/12.680733","url":null,"abstract":"By employing a combined optical/electronic model, we investigate the effect of electronic properties on the performance of three layer organic semiconductor structures, which are a potential candidate for future electrically pumped organic laser diodes. The drift-diffusion equations which describe particle transport are coupled to the spatially inhomogeneous laser rate equations to solve for the dynamics of the excited state and photon population in the laser cavity. Due to the high current densities considered, high particle densities occur, which implies that annihilation processes between the different particle species have to be considered. On the optical side, we take into account the absorption of the metal electrodes required for current injection to obtain the intensity profiles of the guided modes. Our calculations show that the inclusion of annihilation processes leads to a strong dependence of the laser threshold on the charge carrier mobilities, in contrast to the situation when exciton annihilation is neglected. We observe optimum values for the charge carrier mobilities in the emission layer regarding the threshold current and power density. On the other hand, an increase of the mobilities in the transport layers leads to a reduction of these quantities. The threshold voltage decreases for increasing mobilities, regardless of the layer in which the mobility is increased. For optimised values, we obtain a threshold current density of jthr = 267 A/cm2 with annihilation processes taken into account. The presented results can serve as guidelines in the search for material combinations and devices structures suitable for electrically pumped organic semiconductor laser diodes.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129167244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Design strategies for achieving high triplet energy electron transporting host materials for blue electrophosphorescence 实现蓝色电磷光高三重态能量电子输运主体材料的设计策略

SPIE Optics + Photonics Pub Date : 2006-12-05 DOI: 10.1117/12.684126

L. Sapochak, A. Padmaperuma, P. Vecchi, Hong Qiao, P. Burrows

引用次数: 20

Chemosensory lasing action for detection of TNT and other analytes 用于检测TNT和其他分析物的化学感应激光作用

SPIE Optics + Photonics Pub Date : 2006-12-05 DOI: 10.1117/12.683988

A. Rose, Z. Zhu, C. Madigan, T. Swager, V. Bulović

引用次数: 4