A novel unstable exte
rnal cavity fo
r a b
road a
rea lase
r diode is p
resented. The cavity is based on a V-shaped setup that imp
roves the slow axis beam quality by coupling the inte
rnal modes of a gain guided lase
r diode. The novelty he
re is the compact unstable
resonato
r design without lenses in di
rection of the slow axis. Fo
r f
requency stabilisation and to na
rrow the line width of the lase
r diode emission a diff
raction g
rating in a Litt
row configu
ration is used. With this setup up to 1 W of nea
r diff
raction limited light with a beam quality of
M2 ![]()
rc="http://www.sciencedi
rect.com/scidi
rimg/entities/2a7d.gif" alt="less-than-o
r-equals, slant" bo
rde
r=0> 1.3 and a line width of 1.7 MHz could be achieved. The exte
rnal cavity lase
r was tunable ove
r a
range of 35 nm (FWHM) a
round the cente
r wavelength of 976 nm.