This work describes a graded reflectivity mirror design for tunable Ti:sapphire laser cavities. A mirror was designed and fabricated in the Thin Film Laboratory at the Dipartimento di Ingegneria Elettrica of the Universita di Palermo, and tested in the Laser and Lidar section at CISE. The aim was to fabricate a high damage threshold GRM whose super-Gaussian parameters (R 0=0.5, W m=1.8, n=3) are constant in the 750-850 nm band. Laser induced physical vapour deposition was chosen as the fabrication technique; the shadowing effect of a non-contacting mask produces graded-thickness thin films whose shape is predicted by a mathematical model based on geometrical considerations. A spatially scanned, in situ monitoring system at several wavelengths allows accurate measurement of the reflectivity profile during the deposition of each layer. Starting from a four-layer structure of ZrO 2 and MgF 2 over a Schott SF6 glass substrate, a numerical refinement of the design has been performed, by varying both maximum film thickness and evaporation system geometrical parameters, in order to optimize a suitable quality factor. The mirror has been tested as the output coupler in a Ti:sapphire laser cavity, generating 40 mJ-10 ns pulses without damage; the maximum estimated energy density was about 1 J cm -2.
A simple GRM design for tunable Ti:Sapphire laser
PACE, Calogero;
1994-01-01
Abstract
This work describes a graded reflectivity mirror design for tunable Ti:sapphire laser cavities. A mirror was designed and fabricated in the Thin Film Laboratory at the Dipartimento di Ingegneria Elettrica of the Universita di Palermo, and tested in the Laser and Lidar section at CISE. The aim was to fabricate a high damage threshold GRM whose super-Gaussian parameters (R 0=0.5, W m=1.8, n=3) are constant in the 750-850 nm band. Laser induced physical vapour deposition was chosen as the fabrication technique; the shadowing effect of a non-contacting mask produces graded-thickness thin films whose shape is predicted by a mathematical model based on geometrical considerations. A spatially scanned, in situ monitoring system at several wavelengths allows accurate measurement of the reflectivity profile during the deposition of each layer. Starting from a four-layer structure of ZrO 2 and MgF 2 over a Schott SF6 glass substrate, a numerical refinement of the design has been performed, by varying both maximum film thickness and evaporation system geometrical parameters, in order to optimize a suitable quality factor. The mirror has been tested as the output coupler in a Ti:sapphire laser cavity, generating 40 mJ-10 ns pulses without damage; the maximum estimated energy density was about 1 J cm -2.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
