Lasing characteristics of gas mixtures involving UFG: Application to nuclear pumping of lasers

Intense blue-green fluorescence from a structured band centered at lambda approximately 484 nm was observed from Ar, CF3I and NF3 gas mixtures excited by an electron beam. This emission was tentatively assigned to the E yields A transition of the iodine monofluoride (IF) molecule. The fluorescence efficiency of the IF(E yields A) band and the IF (E) state radiative lifetime were estimated to be approximately 6% and 15 ns, respectively. The emission band structure, the short IF(E) radiative lifetime and the Franck-Condon shift between the E and A states suggest that IF is an attractive candidate for a blue-green laser

A gain-coefficient switched Alexandrite laser

We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.Comment: 8 pages, 5 figure

Studies of discharge mechanisms in high pressure gases-applications to high efficiency high power lasers

By measuring the absorption and emission cantinua of various states in the cesium/xenon molecule, the collisional rates critical in populating the alkali/rare gas excimer levels have been estimated. Cs atomic states that are weakly optically connected to ground have been shown to form excimer levels that are attractive as potential dissociation lasers. In particular, the (Cs/7 2S/Xe) excited molecule appears promising as a source of high energy laser radiation due to its large dissociation energy, stimulated emission cross section, and small population inversion densities. Monitoring of the optically pumped Cs2 molecular absorption profile in the presence of xenon shows a drastic change with increasing xenon pressure for the Cs2C band. Dominant absorption at large xenon densities is centered around approximately 6380 A as opposed to 6300 A for lower perturber pressure

Advanced methods for nuclear reactor gas laser coupling

Research is described that led to the discovery of three nuclear-pumped lasers (NPLs) using mixtures of Ne--N/sub 2/, He--Hg, and He or Ne with CO or CO/sub 2/. The Ne--N/sub 2/ NPL was the first laser obtained with modest neutron fluxes from a TRIGA reactor (vs fast burst reactors used elsewhere in such work), the He--Hg NPL was the first visible nuclear-pumped laser, while the Ne--CO and He--CO/sub 2/ lasers are the first to provide energy storage on a millisecond time scale. Important potential applications of NPLs include coupling and power transmission from remote power stations such as nuclear plants in satellites and neutron-feedback operation of inertial confinement fusion plants

Studies of basic mechanisms in high pressure gases: Applications to high efficiency high power lasers

A high power pulsed dye laser was used to optically excite high pressure cesium-xenon mixtures and the resulting measurements are presented. A microwave discharge in rubidium at relatively high xenon pressure was achieved. Preliminary studies of cadium-rare gas mixtures are discussed and a detailed description of the entire experimental apparatus is given

A Method for Evaluating Humanoid Robots Using Anthropometric and Biomechanical Data

No abstract availabl

Raman Laser Switching Induced by Cascaded Light Scattering

It is shown that, in multimode Raman lasers, cascaded light scattering (CLS) not only extends the optical frequency range, but can also modulate the laser dynamics. The origin of this phenomenon lies in the fact that many Raman lasing modes are directly correlated through CLS. The coupled‐mode equations only describe single‐mode cascaded Raman lasers and are insufficient for describing the multimode case. In this work, additional terms are introduced to account for intermodal interaction and, therefrom the physical mechanism behind the mode‐switching phenomenon is revealed. Additionally, mode‐switching controlled solely by a single‐mode pump in a whispering gallery mode (WGM) silica Raman laser is demonstrated. As the intracavity pump power is increased, laser switching happens between two adjacent WGMs in the same mode family

Centaur: NASA’s mobile humanoid designed for filed work

Abstract -NASA's future lunar and martian missions will require a suite of advanced robotic systems to complete tasks during precursor visits and to assist humans while present on the surface. The Centaur is a new mobile, dexterous manipulation system designed with this future role in mind. Centaur combines the sophisticated upper body dexterity of NASA's humanoid, Robonaut, with a rugged and versatile four-wheeled base. This combination allows for robotic use of human tools and interfaces in remote locations by incorporating design improvements to the existing Robonaut that target the challenges of planetary field work: rough terrain, a varied environment (temperature, dust, wind, etc.), and distance from human operators. An overview of Centaur's design is presented focusing on the features that serve to mitigate the above risks and allow the robot to perform human-like tasks in unstructured environments. The success of this design is also demonstrated by the results of a recent coordinated field demonstration in which Centaur, under both teleoperated and autonomous control, cooperated with other NASA robots

Role of Excited State Photoionization in the 852.1 nm Cs Laser Pumped by Cs-Ar Photoassociation

Photoionization of Cs (6p 2P3/2) atoms during the operation of a Cs D2 line (852.1 nm: 6p 2P3/2→6s 2S1/2) laser, pumped by free→free transitions of thermal Cs-Ar ground state pairs, has been investigated experimentally and computationally. Photoexcitation of Cs vapor/Ar mixtures through the blue satellite of the D2 transition (peaking at 836.7 nm) selectively populates the 2P3/2 upper laser level by the dissociation of the CsAr excited complex. Comparison of laser output energy data, for instantaneous pump powers up to 3 MW, with the predictions of a numerical model sets an upper bound of 8 × 10−26 cm4 W−1 on the Cs (6p 2P3/2) two photon ionization cross-section at 836.7 nm which corresponds to a single photon cross-section of 2.4 × 10−19 cm2 for a peak pump intensity of 3 MW cm−2