How does our Professional laser tune modehop-free ?

Cavity Modes Ca vi ty M odes

Physical Basics Technical Solution Technical Realization

The emission wavelength of a laser isdefined by two features. The first con- ditionis the cavitymode.The se- cond condition is the amplification rangeof the gain medium. Since diode lasers manufacturer have an extremely wide gain region, it is necessaryto put a wavelength selective medium inside of the cavity like a grid. In order to tune such a laser modehop-free, it is required to synchronize the grating defined wavelengthwith the cavitySacher Lasertechnikhas realized thesynchronization between grating de- fined and cavity defined wavelength by only a simple rotation of the mirror. The adjustment of the pivot point is done during the wavelengthscanning operation of our Littman/Metcalf laser system according to our patent no. 5,867,512. Due to this special method, we are able to ensure the best mode- hop free tuning behavior. An increaseof the output power and the total per- formance of the Littman/Metcalf laser is achieved by using a high efficiency grating and outcoupling the light of the rear facet of the laser diode suppliers. With this approach, we are able to increase the outputpowerto more than 100mW.The drawings on the left hand sideshow the technical realization and thedimensions of the TEC-500 and the TEC-520 external cavity diode laser systems. Due to using a alignment insensitive cavity design and a flex- mountconcept, our Littman/Metcalf laser diode systems are excellent turn-key devices.

Grating

Wa Wavelength ve le ng th

P Pivot PointLaserTuning Mirror iv ot P oi nt La se r Tu ni ng M irr or
TEC-500 x x 2 1

defined wavelength [1].

x x 3 Grating G ra tin g Tuning Mirror Tu ni ng M irr or
TEC-520 x 3 Laser La se r
x 2 Grating G ra tin g
x 1 Pivot Point P iv ot P oi nt

Dimensions

TEC-500 98mm 80mm 5mm 180mm [1] M. G. Littman, H. J. Metcalf, Appl. Opt. 17, 2224, 1978 TEC-520