Signal beam

About: Signal beam is a research topic. Over the lifetime, 1881 publications have been published within this topic receiving 20717 citations.

Mid-infrared all solid state DIAL for remote sensing of hazardous chemical agents

Abstract: We describe all solid state differential absorption lidar (DIAL) based on the mid-infrared (IR) tunable Optical Parametric Oscillator (OPO). Generation of tunable mid-infrared laser radiation using a two stage tandem OPO was demonstrated. The first stage was based on the nonlinear KTP crystal and produced up to 45 mJ of 1.57 m radiation, while pumped by a commercial Q-switched Nd:YAG laser. The quality of signal beam was improved by the use of unstable resonator. The AgGaSe2 crystal was used in the second stage OPO. Idler energies up to 1 mJ were generated at this stage within tuning range from 6 to 12 m. The receiver consisted of a 250 mm gold mirror telescope, two channel detection system and control electronics. We have designed a photoacoustic cell for wavelength calibration of lidar. Preliminary lidar field test results are presented.

Method of choosing an optimum angle between a reference beam and an object beam to record a hologram

Abstract: A method of choosing an angle between a reference beam and a signal beam in a holographic storage apparatus is presented. The angle between the reference and signal beams can be optimized in light of crosstalk, scattering and wavelength seperation considerations.

Application of a pulsed OPO seeded by a CW OPO to investigation of linewidth effects on TALIF excitation efficiency

Abstract: In this article we present a widely tunable laser architecture for high-resolution nonlinear spectroscopy which incorporates a continuous wave optical parametric oscillator (OPO) for injection-seeding of a singly resonant actively-locked β - Ba ( BO 2 ) 2 nanosecond OPO. Such an instrumental configuration is designed to provide near-transform-limited pulses over 450–650 nm signal, and 225–325 nm after signal doubling. Novel features that enable frequency agility and ramp-lock injection-seeding over a wide frequency range are described. System performance was demonstrated through investigations of two-photon laser induced fluorescence (TALIF) and the influence of excitation linewidth on the signal strength of the 5 p 6 S 0 - 6 p [ 3 / 2 ] 2 transition of atomic xenon at 252.49 nm. Measurements conducted at xenon partial pressures of 1 × 10 - 1 - 4 × 10 - 4 Torr, with and without active cavity locking and injection seeding, resulted in a 17 × increased TALIF fluorescence yield during injection-seeded operation. The results are found to be consistent with modeling, taking into account the effects of lineshape, energy, and beam spatial cross-section. Modeling was informed by direct single-shot measurements of the signal beam lineshape in seeded and free-running operation using a virtually imaged phased array (VIPA) spectrometer.

Saturable absorber intensity modulator

Abstract: We propose and demonstrate a reflection-type optical modulator, with surface-normal architecture that exploits saturation of absorption in semiconductor quantum wells pumped optically. The modulation section, composed of quantum wells placed within a Fabry-Perot cavity, is exposed to an intensity-modulated beam generated by an in-plane laser integrated monolithically on the same wafer. Since the modulation section and the in-plane laser share the same medium, an efficient coupling between the control beam and the signal beam is achieved. Design guidelines and device performance are presented. We demonstrate that the modulator provides an efficient light modulation mechanism that is sufficient to actively mode-lock an erbium-doped fiber laser.

Apparatus for recording/reproducing holographic data

Abstract: A holographic information recording and/or reproducing apparatus includes: a light source to emit light; a polarization conversion device to form a polarized signal beam and an orthogonal polarized reference beam; an optical path forming optical system to separate the optical paths of the signal beam and the reference beam; a focus adjustment optical system disposed on the optical path of at least one of the signal beam and the reference beam, and to vary a position of a focus of at least one of the signal beam and the reference beam in a depth direction of the holographic information storage medium; an objective lens to focus the signal beam and the reference beam in the holographic information storage medium, and form an interference pattern to record information; and a 4f relay system disposed on an optical path between the focus adjustment optical system and the objective lens.