Vertical pin-modulator for controlling an external-cavity diode laser

In this paper, a vertical pin-modulator is described, which replaces the standard backside mirror of the external cavity in a Littman-type laser system. By controlling the reflectivity of the pin-modulator the power of the output beam can be modulated. A pin-modulator with a reflectance contrast of about 4 dB leads to a contrast of more than 22 dB of the output power in the laser system. By using an array of vertical pin-modulators in the dispersive external arm of the resonator, whose pixels are matched to the individual wavelength, fast wavelength tuning and multi color operation will be possible.