Research Highlights

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…

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…

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…

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…

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…

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…

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…

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…

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…

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…

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…

The advent of plasmonics has enabled the focusing of visible light down to few-nanometer spot sizes, more than an order of magnitude below the diff raction limit. This extreme focusing enables the optical probing of volumes as small as a thousandth of an att oliter (10-24 m3), enabling biochemical sensors that operate at the few-molecule…