Helical distributed feedback gas laser

Novel Aspects Of Far-Infrared Gas Lasers

“…The concept of helical feedback (HFB) which is based on group theory [13, 19J was first verified on an optically pumped farinfrared gas laser equiped with a helical waveguide for optical feedback [13,18,19]. In the meanwhile it was noticed that HFB is also present in, dye lasers with cholesteric liquid crystals serving as optical feedback [10,11,16,20].…”

All-fibre photonic crystal distributed Bragg reflector (PC-DBR) fibre laser

“…The flexibility in the surface area of fibre glass systems and their photosensitive response enables complex lasing phenomena to be generated that have not previously been observed in solid state lasers. One example is helical feedback operation (HFB) [6], previously only reported in gas lasers [7], but more recently generated in solid state form by twisting a DFB fibre laser after its fabrication or twisting prior to grating writing and subsequently releasing [8]. Thus gratings remain one of the key enabling technologies in photonic components.…”