Shih Tseng

Demonstration of a highly subluminal laser with suppression of cavity length sensitivity by nearly three orders of magnitude

We have demonstrated a laser in which the frequency shift due to small cavity fluctuations is far less than what would be expected from a conventional laser. The factor of sensitivity suppression is inferred to be equal to the effective group index experienced by the laser, implying that this laser is subluminal. We have observed a suppression factor as high as 663. Such a laser is highly self-stabilized compared to a conventional laser, and is expected to have a far smaller Schawlow-Townes linewidth. As a result, this laser may have potentially significant applications in the fields of high-precision optical metrology and passive frequency stabilization.

Experimental demonstration of the hybrid opto-electronic correlator for target recognition

Optical target recognition using correlators is an important technique for fast verification and identification of images. The hybrid opto-electronic correlator (HOC) recently proposed by us bypasses the need for nonlinear materials such as photorefractive polymer films by using detectors instead, and the phase information is yet conserved by the interference of plane waves with the images. In this paper, we demonstrate experimentally the basic working principle of the HOC architecture using currently available technologies. For matched reference and query images, the output signal shows a sharp peak, indicating a match is found. For an unmatched case, a much lower peak value is observed, indicating no match. We also demonstrate the dependence of the output signal on the phases of the interfering plane waves and describe a technique using an interferometer and a servo for optimizing the output signal. As such, the work reported here paves the way for further development of the HOC for practical applications.

Observation of Raman resonance of a probe in a Rb cell added to an Ethane-Rb laser for realizing a superluminal laser

We report sub-natural linewidth Raman resonance for a probe applied to an auxiliary Rb cell added to an Ethane-Rb laser as a key step towards realizing a superluminal ring laser for ultrasensitive gyroscopy and accelerometry.

Automated Stokesmetric imaging laser radar system

We report the design and implementation of a high-speed, automated laser radar (ladar) system with sensitivity enhanced by a polarimetric imaging technique. This ladar is able to analyze the Stokes vector of the reflected light from a target at video-rate. With a polarization state generator and a polarization state analyzer, the system is capable of performing a complete Mueller matrix imaging of the scene under observation. This polarization-sensitive ladar (pladar) is applied to various scenes and found to yield the ability to detect information that is indiscernible to a conventional, intensity-based ladar.

Ultra-low Power Optical Modulation within Tapered Nano-fiber using 5S-5P-5D Ladder Transition of Rb Atoms

We show, theoretically and experimentally, how an optical modulator can be realized within 5S-5P-5D ladder transition of Rb atoms inside a tapered nano-fiber.

An Inhomogeneously Broadened Superluminal Ring Laser for Rotation Sensing and Accelerometry

We show how a superluminal ring laser can be realized using an inhomogeneously broadened gain medium with the addition of a dip in the gain profile, for application to enhanced precision rotation sensing and accelerometry

An Automated Stokesmetric Imaging Laser Radar

We report an automated Stokesmetric imaging eye safe laser radar that can detect all four components of the Stokse parameters in the reflected signal, with a variable input polarization state, capable of full Mueller-metric imaging.

Demonstration of a spectrally multiplexed holographic stokesmeter

A holographic Stokesmeter utilizes polarization sensitivity of volume gratings to determine the Stokes parameters of an input beam. We demonstrate a spectrally multiplexed holographic stokesmeter for two different wavelengths of 532nm and 780nm simultaneously