Light Guiding by Artificial Gauge Fields

December 31, 2019 by
Gauge fields are a fundamental concept in physics, describing the basic interactions between charged particles. For example, electrons interact with each other through its gauge field, the photon. Neutral particles (such as photons) by being chargeless are thus decoupled from real gauge fields. However, by properly engineering a physical system through its geometric design or […]

Novel mid-infrared lasers for driving “water window” attosecond sources

December 31, 2019 by
The advent of femtosecond Ti:Sapphire lasers in the 1990s leads to the first demonstration for attosecond light in 2001. With commercially available lasers centered at 800 nm as the driver, extreme ultraviolet pulses with up to 150 eV photon energy can now be routinely generated for time-resolved experiments[1]. In recent years, carrier-envelope phase stabilized lasers […]

Clear and wide field of view single-molecule fluorescence microscopy

December 31, 2018 by
Wide-field epi-illumination fluorescence microscopy is an indispensable tool in many biological studies due to its high sensitivity  and high specificity (Fig. 1). Especially, single- molecule  imaging  is  a  powerful  approach for quantitative analysis  since  it  is  capable  of counting the number of molecules in a digital fashion and observing the dynamics of individual molecules in […]

Microdroplet duality for subwavelength focusing in nanomanufacturing

December 31, 2018 by
Much research has been carried out to produce nanoparticles of various materials due to their excellent mechanical, chemical, electrical, and optical properties. However, it is difficult to deposit and transform nanoparticles into large two-dimensional and three-dimensional structures, such as thin films or discrete arrays of nanodots, in a controlled manner. Recently subwavelength phenomena have drawn […]

Laser beam shaping enables high-speed microfabrication

December 31, 2018 by
Ever since lasers were invented almost 60 years ago, they have been used in welding, drilling, cutting, forming and other manufacturing processes. A new generation of lasers has been developed in the past few decades. Commonly referred to as “ultrafast lasers” or “ultrashort-pulsed lasers,” this type of laser can output flashes of light (“pulses”) that […]

Optical Parametric Oscillation First Demonstrated in Random χ(2) Medium

December 31, 2018 by
It has commonly been assumed that perfect crystals are paramount for the operation of frequency converters based on quadratic nonlinearity, χ(2), such as optical parametric oscillators (OPOs). The necessary phase- matching condition is usually achieved either by a proper crystal orientation, or via quasi-phase matching through controlled flipping of crystalline domains. Apparently,  as  our recent results […]

LCD is entering virtual reality

December 31, 2018 by
Virtual reality (VR) is an emerging wearable display technology with potential applications for entertainment, education, training, design, advertisement, and medical diagnostics. Both liquid crystal display (LCD) and organic light-emitting diode (OLED) are applicable for such head-mounted displays. Currently, OLED is a favored choice because of its fast response time, which helps to suppress image blurs […]

Curved Image Sensors

December 31, 2017 by
Imaging systems have grown to become ubiquitous pieces of technology found in an ever-increasing range of applications including cell phones, self-driving cars, and refrigerators that photograph their insides. This growth has been facilitated by mobile devices, which have driven camera technologies to smaller form factors and lower cost. Despite individual component advances and the transition […]

New Sensors for Infrared Imaging Systems

December 31, 2017 by
Infrared imaging systems encompass a wide variety of technologies and applications. Technologies range from new infrared detector materials and devices to new optical materials and methods. The applications are primarily military, but security and commercial applications continue to grow rapidly as infrared components become more affordable. The military applications can be grouped in typical areas […]

Nondegenerate Two-Photon Gain in Semiconductors

December 31, 2017 by
Lasers operate by stimulated emission, where a single photon is emitted per electronic transition. Two photons, with combined energy matching the transition energy, can also stimulate emission of two additional photons in a process known as two-photon gain (2PG). Just as linear (single-photon) absorption changes into stimulated emission with population inversion, two-photon absorption (2PA) changes […]

Enabling new optical functionality through multi-phase IR materials

December 31, 2017 by
Chalcogenide glass (ChG) – based optical materials that transmit throughout the infrared (IR) have seen increasing use in a diverse range of infrared optical system. In recent years, traditional IR optical systems for the mid-wave infrared (MWIR) and long-wave infrared (LWIR) based solely on ZnS and ZnSe, Si, Ge, and other semiconductor crystalline materials have […]

Self-Contained On-chip Integrated Sensor of Biomolecular or Chemical Agents

December 31, 2016 by
Highly portable compact integrated sensors that are capable of fast response times are very attractive and in great demand for many applications in the medical field as well as for homeland security purposes. In order to have sensor modules that are fully integrated on-chip, it is imperative that both active and passive devices be compatible […]