Effective bandwidth reduction for a high-power laser-diode array by an external-cavity technique

Abstract

bandwidth of a high-power laser-diode array was effectively suppressed by use of an off-axis external-cavity technique. The external cavity consisted of a beam-transformation system and a pair of off-axis volume Bragg gratings. During operation at a drive current of 40 A, we reduced the bandwidth's full width at half-maximum from 3.3 to 0.24 nm (14-fold reduction) and achieved an output power of 20 W, or as much as 87% of the power radiated by a free-running laser-diode array without an external cavity.

Alkali lasers for magnetic resonance imaging

“…A combination of these two approaches, LDA line narrowing and buffer gas pressure increase, can also be considered. Several methods utilizing different kinds of external cavities with wavelength sensitive elements have been developed [19][20][21][22] that significantly narrow the LDAs linewidth. In our experiments [23] we used holographic plane reflection grating and succeeded in narrowing the LDA linewidth to 11 GHz that well fits to the Cs absorption line broadened by a 1 atm buffer gas.…”

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

“…A distributed-feedback laser diode (LD) emitting 1 W within 0.1 nm spectral linewidth was demonstrated in [4]. 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.…”

Static wavelength scanning using tunable external cavity laser diode

“…2 In particular, if an output facet of the LD is processed with an antireflection ͑AR͒ coating, the LD is strongly coupled to the external cavity. [3][4][5] Tiziani, Franze, and Haible proposed a Littman-cavity-based light source that provided a continuous wavelength tuning range of 25 nm by using an ARcoated LD. 6 A tuning range of 4 nm was obtained with an intracavity glass plate as the fine tuning device, and an AR-coated 633-nm LD in the Littrow configuration.…”