Cesium vapor laser pumped by a volume-Bragg-grating coupled quasi-continuous-wave laser-diode array

Abstract

The experimental demonstration of a broad-area Quasi-continuous-wave (QCW) laser-diode array pumped cesium vapor laser is reported in this letter according to our experimental results. We used a volume-Bragg grating to narrow the spectral linewidth for acquirement of enough resonance transitions. A glass cylindrical cell filled with cesium/buffer gas was set in an end-pumped flat-concave cavity and the gas pressure was set lower than 1atm. Using the QCW drive mode with the repetitive rate and pulse width of 1kHz and 50μs, respectively, 13.45μJ pulse energy has been achieved with the slope efficiency of about ∼1.8%.

Continuous wave, 30 W laser-diode bar with 10 GHz linewidth for Rb laser pumping

“…Single LDs and laser-diode bars (LDBs) integrated into wavelengthselective external cavities with surface diffraction gratings have shown narrowing of linewidths down to tens of gigahertz at power levels of tens of watts [5][6][7][8][9][10]. Conversely, the alkali-vapor lasers have been optically pumped by LD arrays with linewidths exceeding several nanometers (a few terahertz) by using high-pressure buffer gases [11][12][13] to broaden the alkali absorption transition. Recent technological progress with volume Bragg gratings (VBG) recorded in photothermorefractive glass has opened new opportunities for the design and fabrication of compact external-cavity semiconductor laser systems suitable for optical pumping of solid-state, fiber, and gas lasers [14][15][16].…”

“…Approved for public release; distribution unlimited 13 Diode lasers with gigahertz-wide emission spectra have a great potential for applications in Raman spectroscopy, atom cooling, and in the emerging field of optical pumped alkali vapor (cesium, rubidium, and potassium) lasers. Efficient operation of lowerpressure ͑Ͻ1 atm͒ alkali-vapor lasers requires pump sources with a bandwidth that matches the pressurebroadened absorption band ͑ϳ10 GHz͒ of the alkali vapor.…”

“…The thermal shift of the wavelength does not increase the width of the laser spectrum. The absorption of the pump light by Rb atoms was measured in the 25-mm-thick alkali cell at 420 K. The cell contained excess Rb with a vapor phase number density of 7.2ϫ 10 13 at/ cc at 420 K mixed with C 2 H 6 buffer gas (300 Torr at 298 K). This resulted in an absorption transition on the order of 8 GHz (FWHM).…”

Hydrocarbon-free resonance transition 795-nm rubidium laser

“…The first experimental demonstration of an optically pumped alkali resonance laser occurred in 2002 at LLNL in which Rb vapor in a buffer gas mixture consisting of ~70 Torr of ethane and ~500 Torr of He was lased under pump excitation from a Ti:sapphire laser [2]. Since then, several demonstrations of alkali resonance transition lasers have been reported in the scientific literature using Rb [3], Cs [4,5,6] and K [7] as the gain media. A notable mention is the work done by Zhdanov et al which used extremely line-narrowed diode arrays, ∆λ≈10 GHz, to demonstrate 10 W class lasers with optical-optical efficiencies of >60% in Cs [8].…”

Deleterious processes of a diode-pumped cesium vapor hollow-core photonic-crystal fiber laser

“…In the recent years, a diode-pumped alkali laser (DPAL) has been extensively studied due to the potential for its excellent physical features [1][2][3] . The oscillator of a DPAL usually contains an enclosed glass cell, in which the vapor of neutral alkali (K, Rb, Cs) and several kinds of buffer gases (helium and hydrocarbon with small molecular weight) are sealed with a certain pressure [4][5][6] .…”