The spectroscopic application of a new broadband microelectromechanical-system-tunable vertical cavity surface-emitting laser with single-mode coverage of 60 nm (245 cm(-1)) in a single, continuous sweep is described. The operation of the device is illustrated with high-resolution spectra of CO and CO2 over 110 cm(-1) (27 nm) and 67 cm(-1) (17 nm), respectively, with the CO band shown for high-pressure scans between 1 and 3 bars (0.1-0.3 MPa). The achieved tuning range opens up new opportunities for tunable diode laser absorption spectroscopy. The spectra were compared with HITRAN-derived model calculations. The benefits of a sensor based on this laser are greater speed, laser power, and tuning range.

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This letter analyzes the intrinsic optical switching response of state-of-the-art high power, multiquantum wells, thinfilm, and surface-textured infrared light emitting diodes (LEDs). For the switching time response of such devices, the theoretical basics are presented and their predictions are experimentally verified. In the second part of this letter, a novel, fast switching LED driving circuit is presented which enables nanosecond-pulse operation. The circuit reduces significantly the optical rise and fall time of LEDs from 10/15 ns, respectively, down to 2.6 ns at 2-A pulse current without compromising the peak output power.

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