Optical Science Research Articles

Extreme ultraviolet high-harmonic spectroscopy of solids.

Extreme ultraviolet (EUV) high-harmonic radiation emerging from laser-driven atoms, molecules or plasmas underlies powerful attosecond spectroscopy techniques and provides insight into fundamental structural and dynamic properties of matter. The advancement of these spectroscopy techniques to study strong-field electron dynamics in condensed matter calls for the generation and manipulation of EUV radiation in bulk solids, but this capability has remained beyond the reach of optical sciences. Recent experiments and theoretical predictions paved the way to strong-field physics in solids by demonstrating the generation and optical control of deep ultraviolet radiation in bulk semiconductors, driven by femtosecond mid-infrared fields or the coherent up-conversion of terahertz fields to multi-octave spectra in the mid-infrared and optical frequencies. Here we demonstrate that thin films of SiO2 exposed to intense, few-cycle to sub-cycle pulses give rise to wideband coherent EUV radiation extending in energy to about 40 electronvolts. Our study indicates the association of the emitted EUV radiation with intraband currents of multi-petahertz frequency, induced in the lowest conduction band of SiO2. To demonstrate the applicability of high-harmonic spectroscopy to solids, we exploit the EUV spectra to gain access to fine details of the energy dispersion profile of the conduction band that are as yet inaccessible by photoemission spectroscopy in wide-bandgap dielectrics. In addition, we use the EUV spectra to trace the attosecond control of the intraband electron motion induced by synthesized optical transients. Our work advances lightwave electronics in condensed matter into the realm of multi-petahertz frequencies and their attosecond control, and marks the advent of solid-state EUV photonics.

Nanometer level characterization of the James Webb Space Telescope optomechanical systems using high-speed interferometry

The James Webb Space Telescope (JWST) Optical Telescope Element is a three mirror anastigmat consisting of a 6.5 m segmented primary mirror (PM), a secondary mirror, and a tertiary mirror. The primary mirror comprises 18 individual hexagonal segments. The telescope and instruments will be assembled at Goddard Space Flight Center (GSFC) to build the Optical Telescope Element-Integrated Science Instrument Module (OTIS). While at GSFC, the OTIS will go through a series of environmental tests. In these tests the OTIS will be exposed to launch level acoustics and vibrations. To assure that OTIS’s performance has not changed due to these environmental tests, the assembly will be tested optically at the center of curvature of the PM. A high-speed interferometer has been designed and built to characterize both static and dynamic changes due to environmental exposure. This paper describes the details of these measurement techniques. To validate and develop the techniques that will be used on OTIS assembly two spare JWST PM segments were measured and the results presented here.

Marvin Denham Girardeau

Marvin Denham Girardeau

Twenty Years of Laser Cooling of Solids

Laser induced cooling of solids or optical refrigeration is an area of optical science investigating interaction of light with condensed matter. This addresses a very important practical issue: design and construction all optical solid-state cryocoolers, which are compact devices, free from mechanical vibrations, moving parts, or fluids. They are based on reliable diode pump technology and in the most part free from electromagnetic interference in the cooled area. The optical cryocooler has a broad range of applications such as in the development of biomedical sensing, magnetometers for geophysical sensors and other sensors, satellite instrumentations where compactness and the lack of vibration are key parameters. The operation of these devices is based on anti-Stokes fluorescence also known as luminescence upconversion, in which light quanta in the red tail of the absorption spectrum are absorbed in a material from a pump laser and by adding thermal energy, blue-shifted photons are spontaneously emitted. Laser cooling of solids can be realized in rare-earth doped low phonon energy glasses and crystals as well as in direct band gap semiconductors. Both of these areas are very interesting and important and are discussed in this article.

Deformable Surface Accommodating Intraocular Lens: Second Generation Prototype Design Methodology and Testing.

Present an analysis methodology for developing and evaluating accommodating intraocular lenses incorporating a deformable interface. The next generation design of extruded gel interface intraocular lens is presented. A prototype based upon similar previously in vivo proven design was tested with measurements of actuation force, lens power, interface contour, optical transfer function, and visual Strehl ratio. Prototype verified mathematical models were used to optimize optical and mechanical design parameters to maximize the image quality and minimize the required force to accommodate. The prototype lens produced adequate image quality with the available physiologic accommodating force. The iterative mathematical modeling based upon the prototype yielded maximized optical and mechanical performance through maximum allowable gel thickness to extrusion diameter ratio, maximum feasible refractive index change at the interface, and minimum gel material properties in Poisson's ratio and Young's modulus. The design prototype performed well. It operated within the physiologic constraints of the human eye including the force available for full accommodative amplitude using the eye's natural focusing feedback, while maintaining image quality in the space available. The parameters that optimized optical and mechanical performance were delineated as those, which minimize both asphericity and actuation pressure. The design parameters outlined herein can be used as a template to maximize the performance of a deformable interface intraocular lens. The article combines a multidisciplinary basic science approach from biomechanics, optical science, and ophthalmology to optimize an intraocular lens design suitable for preliminary animal trials.

Optical cooling and trapping: introduction

The year 2015 is an auspicious year for optical science, as it is being celebrated as the International Year of Light and Light-Based Technologies. This focus issue of the journals Optics Express and Journal of the Optical Society of America B has been organized by the OSA Technical Group on Optical Cooling and Trapping to mark this occasion, and to highlight the most recent and exciting developments in the topics covered by the group. Together this joint focus issue features 33 papers, including both experimental and theoretical works, which span this wide range of activities.

The Atomic, Molecular and Optical Science instrument at the Linac Coherent Light Source.

The Atomic, Molecular and Optical Science (AMO) instrument at the Linac Coherent Light Source (LCLS) provides a tight soft X-ray focus into one of three experimental endstations. The flexible instrument design is optimized for studying a wide variety of phenomena requiring peak intensity. There is a suite of spectrometers and two photon area detectors available. An optional mirror-based split-and-delay unit can be used for X-ray pump-probe experiments. Recent scientific highlights illustrate the imaging, time-resolved spectroscopy and high-power density capabilities of the AMO instrument.

Focus issue introduction: optical cooling and trapping.

The year 2015 is an auspicious year for optical science, as it is being celebrated as the International Year of Light and Light-Based Technologies. This Focus Issue of the journals Optics Express and Journal of the Optical Society of America B has been organized by the OSA Technical Group on Optical Cooling and Trapping to mark this occasion, and to highlight the most recent and exciting developments in the topics covered by the group. Together this joint Focus Issue features 32 papers, including both experimental and theoretical works, which span this wide range of activities.

Baroque Science by Ofer Gal and Raz Chen-Morris (review)

Reviewed by: Baroque Science by Ofer Gal and Raz Chen-Morris Mary Henninger-Voss (bio) Baroque Science. By Ofer Gal and Raz Chen-Morris. Chicago: University of Chicago Press, 2013. Pp. xiv+ 333. $45. Baroque Science is an ambitious attempt to re-cast our notions of seventeenth-century science entirely. The authors, Ofer Gal and Raz Chen-Morris, specifically eschew the grand narratives of the “scientific revolution.” Instead, they root that revolution’s main protagonists—Kepler, Galileo, Descartes, Newton—within a particular vision of baroque culture, one fraught with paradox and the tensions of the natural/artificial divide. In doing so, they re-inscribe the “revolution” they specifically mention only in passing. Baroque Science is a work of impressive scholarship, enjoyable to read, and an important interpretation for anyone in dialogue with the historiography of seventeenth-century science. The great originality of this book is that Gal and Chen-Morris look at the emergence of an observation-based mathematical natural philosophy with new eyes. They do not fall under the spell of the promoters of this new science, or take as obvious Galileo’s famous dictum that nature is written “in the language of mathematics.” Rather, they unveil seventeenth-century justifications of the new science as “feigning” the pathways between the imputed mathematical structures of nature, new scientific apparatus, and rationality itself. Their fascination is for the ways in which baroque science enforced, rather than uncovered, a mathematical order of physical experience. In Baroque Science, the key to new attitudes toward empirical observation and the mathematization of nature is found in seventeenth-century optics. The authors show that theoretical and practical advances in baroque optics changed what it meant to observe, affected what it meant to imagine, and offered a bridge between the mathematical and physical more immediate and universal than did other “mixed sciences.” Here, both the astronomical revolution and the mechanization of nature are extensions of the new optical sciences and technologies of the century. [End Page 533] In Gal and Chen-Morris’s narrative, Kepler—with his writings on optics and his announcement in Astronomia Nova that mathematicians will invade the territory of physicists—is the central founding father of baroque science. The book covers all the main characters one might find in any standard scientific revolution textbook, but rarely resists overturning conventional interpretations of their work. Gal and Chen-Morris redefine Kepler’s discursive optics against his scholastic forebears and his Aristotelian contemporaries; they re-cast the comet controversy between Galileo and Orazio Grassi as one over optical instrumentation and re-examine Galileo’s distinction between primary and secondary qualities; they invert wisdom on Descartes’ method of doubt; they reexamine the correspondence between Hooke and Newton on the inverse square law as it pertains to commonplaces of optics, and recast Newton as not so much a unifier of seventeenth-century physics as a discursive thinker. In a final chapter, they examine the key role of imagination in the new conceptions of seventeenth-century knowledge, with special attention to the correspondence between Descartes and Princess Elisabeth on the passions. In fact, it is in the imagination, “this most Baroque of the faculties,” that Gal and Chen-Morris claim the real power of the new science lies. As the authors point out, few historians of science have attempted to locate seventeenth-century science on the same canvas with baroque art and culture. Their book is framed by references to art and literature—by Vermeer and Rubens on the art of seeing and Shakespeare on the art of the imagination—and is peppered with the techniques of cultural history. However, these discussions have an illustrative rather than structural role in the argument. Indeed, the interest in capturing motion, in the play of art and nature, in blurring the line between the fantastic and the real, all characterize works of baroque art. Yet we are not really meant to focus on any bleeding between the creative arts and scientific practice, but brought to a better understanding of a broad tapestry that might have grounded the epistemological issues that are the real core of Gal and Chen-Morris’s discourse. This is a rich and ambitious book, but it should not...

A good source of fibre

An Erbium-doped ultrashort pulse fibre laser that matches or surpasses the best solid-state sources is presented in work from Shanghai Jiao Tong University. Based on commercially available components, its creators believe this design could lead to compact, cost-effective, highly stable and reliable laser sources for a vast range of demanding ultrafast laser applications. The experimental setup in the lab at Shanghai Jiao Tong University. The laser is based on commercially available components to provide a more accessible source Ultrashort pulse lasers are important for numerous applications, including micro-machining, surgery, femto-chemistry, terahertz generation, and medical imaging. Some applications, like high-speed fibre communication systems, frequency metrology, photonic analogue-to-digital converters and optical coherence tomography (OCT), also require laser sources that have broadband spectrum and high repetition rate. Fibre lasers, in which the laser amplification medium is a rare-earth doped gain fibre, present a potential alternative to more bulky, expensive and complex solid-state ultra-fast lasers, but only if they can be made to match the performance characteristics – pulse duration, spectrum width, timing jitter and repetition rate – of the best solid-state sources. In their current Electronics Letters paper, the team from Shanghai Jiao Tong University present an Erbium-doped fibre laser that has all these characteristics, combined with simplicity, and is based on commercial components without using any complex fibre structures or materials. The 1550 nm laser has demonstrated 34.3 fs pulses at a fundamental repetition frequency of up to 200 MHz with average output power of 38.5 mW. Its time jitter integrated from 1 kHz to 10 MHz is 24 fs and it generates a broad and flat spectrum with a full width at half magnitude of 148 nm. The main challenge for the Shanghai Jiao Tong researchers was delivering ultrashort pulses whilst achieving high repetition rates. In fibre lasers, gain and loss are fixed by the fibre characteristics in the laser cavity and pulse shaping is regulated by the mutual interactions between chromatic dispersion and optical nonlinear effect. The output characteristics of stretched-pulse fibre lasers are determined primarily by the net group velocity dispersion (GVD), of the whole cavity and, to a lesser extent, by the lengths of the fibres composing the cavity. With regard to optical nonlinear effect, if the accumulated nonlinear phase shift is too small, mode-locking action of laser, based on nonlinear polarisation rotation, can't be implemented effectively. On the other hand, excessive nonlinear phase shift can saturate the mode-locking behaviour and lead to optical wave breaking or multiple pulse operation. In this work, these two factors have been controlled through careful selection, combination and arrangement of three different commercial fibres to form the laser cavity. The resulting cavity has a net GVD near zero and optimally controlled nonlinearity. The polarisation state in the cavity is optimised via fine tuning of the waveplates and pump power, and a prism pair is used outside the cavity to provide external pulse compression (dechirping) of the broadband laser. “It has a lot of potential for applications in wavelength-division multiplexing-based optical sampling to achieve hundreds of parallel channels, and in long haul optical communications networks, where a hundred different closely spaced channels of data are simultaneously transmitted in an optical fibre, with each channel sent by a slightly different laser wavelength,” said team member Prof. Weiwen Zou. The pulses are shorted from 49.1 fs to 34.3 fs by dechirping the output from the laser cavity using an external prism pair “This laser already satisfies many of the requirements for ultrafast optical science. It could increase the performance and range of applications, including femtosecond laser frequency comb generation for optical ultra-precise distance measurements, ultrahigh-resolution molecular spectroscopy, large dynamic range and high-speed fibre Bragg grating strain sensor interrogation, and high-resolution OCT, which have been extensively demonstrated in recent years.” The team say that the laser could be used almost immediately in high-speed and high-resolution photonic analogue-to-digital conversion systems that require hundreds of parallel channels, where electronic analogue-to-digital converters are severely limited; as well as ultra-low phase noise generation of radiofrequency and microwave signals for applications of coherent radar imaging systems, and scientific facility synchronisation.

소형 텔레센트릭 카메라 광학계의 재귀반사 측정 방법 연구 및 측정 장치 개발

이 논문에서는 소형센트릭 카메라의 광학적 특성이 분석적, 실험적으로 연구되었다. 광학적 특성으로 소형센트릭광학계의 재귀반사 광도계수가 조사되었다. 우선, 시뮬레이션을 통해서, 이론적 재귀반사광도계수 값을 측정하였다. 두번째로, 소형센트릭 카메라 장치를 디자인 하였으며, 이후 실험을 통해 실제 장치의 재귀반사광고계수를 측정하였다. 시뮬레이션과 시험을 통해, 재귀반사광도계수의 측정치 및 실험치 모두가 (P384200CPH: <TEX>$0,0042m^2/sr{\sim}0,018m^2/sr$</TEX>, P285200CPH: <TEX>$0,0045m^2/sr{\sim}0,0297m^2/sr$</TEX>, P321450S: <TEX>$0,0021m^2/sr{\sim}0,00963m^2/sr$</TEX>) 1.4 ~ 4.9의 분각에서 <TEX>$0,002{\sim}0,03m^2/sr$</TEX>의 범위에 있음을 발견하였다. 이 결과는, 실제 장비를 구상하는데 사용된 메커니즘과 실험방법의 중요성(유효성)을 증명한다. 이에따라, 이 유효한 결과를 통해서, 이 연구는 광학공학의 이론과 실제의 발전에 기여하였다. In this paper, the optical properties of a miniature telecentric camera are studied analytically and experimentally. By means of optical properties, the luminous intensity of retro-reflection of a miniature telecentric optical system is investigated. First, from a simulation the theoretical value of the coefficient of luminous intensity of retro-reflection of a miniature telecentric system is estimated. Second, a miniature telecentric camera device is designed, and the value of the coefficient of luminous intensity of retro-reflection of the actual device is measured through experiment. From simulation and experiment, we found that both the estimated and observed values of the coefficient of luminous intensity of retro-reflection range from 0.002 to <TEX>$0.03m^2/sr$</TEX> (P384200CPH: <TEX>$0.0042-0.018m^2/sr$</TEX>, P285200CPH: <TEX>$0.0045-0.0297m^2/sr$</TEX>, P321450S: <TEX>$0.0021-0.00963m^2/sr$</TEX>) at 1.4 to 4.9 arcminute. The results prove the significance of the mechanisms used to design the miniature telecentric camera, and the experimental method. Accordingly, with these significant results, this study contributes to the development of theory and practice in optical engineering science.

IYL 2015 in Poland

Abstract Light plays a key role in human’s life. Without light there will be no human life environment. Technologies based on light, called photonics, decide of the development of our civilization. The role of photonics is constantly increasing, especially in such fields as energy, education, agriculture and health. The UN has established the International Year of Light and Light - based Technologies – IYL2015 [1]. The organizers of IYL2015 events are professional organizations, communities, educational organizations, non-profit ones, technological clusters and platforms, but also private sector. The aim is to increase the social consciousness about the role of light and photonics in building of our civilization. This sort of recognition is necessary as a needed component of the development process of the society. Introduction of new technologies, like completely new kind of lighting, new diagnostic and therapeutic methods, new sources of energy, etc., must meet with social acceptance. In the opposite case, isolated development of infrastructure, will meet with obstacles. In Poland, the professional events, technical, trade fairs and outreach ones, are organized in the framework of the IYL2015 by Photonics Society of Poland, Polish Physical Society, Polish Platform of Photonics Technologies, etc. The paper summarizes the issues combined with the organization of the IYL2015 globally and in Poland. Extended version of this paper was published in Polish [2]. The paper is a part of a cycle of articles devoted to analysis of global processes of photonics development. Previous papers concerned initiatives Photonics21 in Europe [3-4], NPI – National Photonics Initiative in USA [5], and development of optical sciences in Poland [6-15].

Forty Years of X-Raying Narrow-Line Seyfert 1 Galaxies

Forty years after the discovery of Narrow-Line Seyfert 1 Galaxies (NLS1s), and 20 years since the discovery of the remarkable ultrasoft soft X-ray emissions of NLS1s, strategic publications improved the understanding of the Seyfert phenomenon more generally. New theoretical models emerged from the observations and stimulated the discussions on the innermost regions of AGN. NLS1s are an amazing class of AGN for X-ray, optical and multiwavelength science.

Generation of sub wavelength focal spot with large depth of focus generated by radially polarized beam

We investigate the focusing properties of a radially polarized Bessel Gaussian beam by a high numerical aperture (NA) lens based on vector diffraction theory. We observe that our proposed system generates a sub wavelength focal spot of 0.42λ having large uniform focal depth of 6.45λ. The authors expect such a long depth of focus have great potential for use in optical, biological, high-resolution and atmospheric sciences.

Molecular Imaging in the College of Optical Sciences - An Overview of Two Decades of Instrumentation Development.

During the past two decades, researchers at the University of Arizona's Center for Gamma-Ray Imaging (CGRI) have explored a variety of approaches to gamma-ray detection, including scintillation cameras, solid-state detectors, and hybrids such as the intensified Quantum Imaging Device (iQID) configuration where a scintillator is followed by optical gain and a fast CCD or CMOS camera. We have combined these detectors with a variety of collimation schemes, including single and multiple pinholes, parallel-hole collimators, synthetic apertures, and anamorphic crossed slits, to build a large number of preclinical molecular-imaging systems that perform Single-Photon Emission Computed Tomography (SPECT), Positron Emission Tomography (PET), and X-Ray Computed Tomography (CT). In this paper, we discuss the themes and methods we have developed over the years to record and fully use the information content carried by every detected gamma-ray photon.

Complete representation of a correlation singularity in a partially coherent beam.

An understanding of phase singularities of correlation functions is important in optical coherence theory and imaging science, but to date such singularities have only been theoretically studied in a single transverse plane, at most. In this Letter we evaluate the complete structure of a correlation singularity of a partially coherent Laguerre-Gauss beam, describing it in both the transverse and the propagation directions. These results agree with previously found solutions, and introduce new aspects of correlation singularities.

OSC Turns 50

The story of the University of Arizona’s College of Optical Sciences begins with Arizona’s amazing blue sky—blue sky that turns to jet-black night, attracting astronomers who want optics bigger and better than anything made before; and blue-sky thinking, inspiring breakthroughs in quantum optics and imaginative new technologies.

Beamline optics layout preparation and evaluation of an undulator based atomic molecular and optical science research beamline at Indus-2 synchrotron radiation source

A planar permanent magnet undulator based beamline for atomic, molecular and optical science research is proposed on Indus-2, a third generation synchrotron light source, at Raja Ramanna Centre for Advanced Technology, Indore, India. A varied line spacing plane grating monochromator in a converging beam and constant included angle mode is used for obtaining monochromatic light in this beamline. This monochromator contains a toroidal focusing mirror and four interchangeable gratings in a new orientation to disperse photons in the energy range of 6–250 eV. We have obtained resolving powers ~104. Details of the methodology followed in evaluation of new mounting proposed for varied line spacing plane grating monochromator, preparation and optimization of beamline optical layout, imaging properties, resolution attainable and intensity at sample position are presented in this paper.

Cross modulation of two laser beams at the individual-photon level.

Deterministic photon-photon interactions are a long-standing goal in optical science. Using an atomic ensemble inside a cavity, we demonstrate the mutual cross modulation of two continuous light beams at the level of individual photons. The originally uncorrelated beams derived from independent lasers become anticorrelated, as evidenced by an equal-time cross-correlation function g^{(2)}=0.89(1), showing that one photon in one beam extinguishes a photon in the other beam with a probability of 11(1)%. With further technical improvements, our approach should enable the nondestructive continuous detection of traveling optical photons.

Two-dimensional discrete Anderson location in waveguide matrix

Anderson location is an important wave phenomenon when the system contains disorder. Anderson location of light is a significant topic in optical science. Arrays of evanescently coupled waveguides made of nonlinear materials are the fundamental model of discrete nonlinear optics. Guided propagation of light in such arrays emulates electronic wave functions in fundamental periodic and disordered potentials of solid state physics. In this work, the Anderson location effect in a two-dimensional waveguide matrix is studied, and the influence of the nonlinearity on the localized effect induced by the disorder of the system is considered.