Comparative studies ofnewoptical feedback concepts forfrequency stabilization oflaser diodes

Summary: Diode lasers under optical feedback condititons areattractive candidates formanyapplications like spectroscopic experiements. Recent investigations innewoptical feedback concepts shownewcapabilities. Theallready knownconcepts ofgrating lasers orexternal cavity lasers [11 exhibit small mode-hop-free tuning ranges withnarrow linewidths orcomplementary properities forconcepts comprising agrating. Obviously thecombinaton ofbothconcepts could marrynarrow linewidths withlarge continous tuning ranges. Wecombined agrating withanexternal cavity placed inthe1storder ofdiffraction. Thisconceptforoptical feedback originally suggested byBelenov etal.[21 usesaresonant three-mirror cavity andavolume-holographic transmission. Ourtheoretical models predict stable longitudinal single mode operation forvarious external cavity designs. Investigations oncoupling effects werecarried outinorder toexplain measured quantities. Wedemonstrate alinewidth of35kHzwithasingle modediode laser operating at852nmphase-locked toanother laser system that isfrequency locked toaCs-transition. A large continous tuning range inexcess of45GHzandsingle modeoperation wereshownfrom829.2 nm to874.1 nmatconstant diode temperature. Theexternal cavity isstabilized tothelaser emission by meansofapolarization dependent methodproposed byHiinsch andCouillaud, leading toalong-term stable lasersystem withtheimpressive features mentioned above. Additionaly thewavelength ofthe wholesystem isconvincingly easytotune.