Frequency locking to absorption lines by wave competition in a tunable ring dye laser

It is proposed that the competition between the two traveling waves be used to obtain optically an inverse laser intensity control, for example, a beam intensity increase directly related to a sample absorption increase. A new type of tunable ring cavity using an interference wedge, which permits good unidirectionality by virtue of an external mirror, is described. A diagram illustrating the principle underlying a tunable ring cavity with an interference wedge is included. The unidirectional ring cavity is seen as being applicable whenever a laser frequency has to be locked to a particular atomic frequency as for example, in cases of isotopic laser separation and atmospheric laser studies. This type of oscillator will be convenient for the experimentalist since it offers good security against tuning errors owing to its automatic and delay-free switch-off in case of accidental detuning.