Electrooptical device for tuning at dye laser wavelength

Electrooptical device for tuning the wavelength of a dye laser by means of a small control voltage and over a frequency range from ultra-violet to infrared, comprising:

• a sealed active head fitted in a laser cavity having an optical axis aligned with an optical axis of the cavity, and including a set of at least two crossed electrooptical crystals of cut X45.degree. or Y45.degree. with transverse electric field, oriented 90.degree. with respect to each other, having neutral lines lying at 45.degree. from a plane of polarization of light passing through said sealed active head, and of different lengths so as to introduce, by natural birefringence, a slight nonzero optical retardation:
• .DELTA.=K.lambda..sub.1 .lambda..sub.2 /(.lambda..sub.1 +.lambda..sub.2) (in .mu.m)
• adapted to the scanned range (.lambda..sub.1, .lambda..sub.2) and to a given emission line width, .lambda..sub.1 and .lambda..sub.2 being the extreme wavelengths of the frequency range to be scanned and K being an integer or close to an interger determining an emission line width, and wherein said sealed active head also comprises a passive birefringent component whose natural birefringence helps increase said nonzero optical retardation .DELTA. and adjust said emission line width, and wherein said sealed active head contains an index adaptor liquid in which said crystals and said passive birefringent component are immersed, and wherein circuits are associated with the sealed active head to apply to electrodes connected to said crystals an adjustable electric voltage that induces an electric field perpendicular to the optical axis of the cavity and, by induction of an additional electric birefringence, make it possible to tune the wavelength of laser radiation emerging from the cavity.