Leysop tunable isolators as described above are ideal for fixed wavelength operation or where only occasional adjustment is required between experiments when the source wavelength has been changed. These adjustments however are relatively time consuming to make and are not convenient where a broadband or rapidly tunable source such as a dye laser or one of the new classes of vibronic mode lasers such as Ti:Sapphire are used. There is not much point in having a laser source which can be tuned to a different wavelength within seconds if the Faraday isolator in the system requires removing from the bench/equipment and set up off line for optimum performance. This is where Leysop’s new broadband units come into their own.
By inserting a passive optical element (Quartz rotation plate) into the device in addition to the TGG rod, the combination of the two components is an isolator in which the the output polarization is now at the more convenient angle of 90° with respect to the input. More importantly, it can be shown that the isolation of the unit is now maintained over a wide bandwidth instead of at just one wavelength.