Tunable terahertz-wave generation from DAST crystal pumped by a monolithic dual-wavelength fiber laser

Abstract

For developing a continuous-wave (CW) tunable Terahertz-wave (THz-wave) source using difference-frequency generation (DFG) in highly nonlinear optical crystals, we proposed and demonstrated a dual-wavelength fiber ring laser system operating around 1060 nm based on wideband chirped fiber Bragg gratings (CFBGs) and semiconductor optical amplifier (SOA). Thermo-induced phase shift along the CFBG produces a very sharp transmission spike therefore two lasing wavelengths with single longitudinal mode operation are oscillating simultaneously within the fiber ring cavity. Due to the inhomogeneous gain broadening property of SOA, the wavelength spacing of our dual-wavelength fiber laser can be continuously adjusted from 0.3 to 9.5 nm. By using this single emitter dual-wavelength fiber laser to pump an organic nonlinear DAST crystal, type-0 collinear phase matching of DFG process can be fulfilled and monochromatic THz wave ranging from 0.5 to 2 THz has been successfully generated.

Optical bistability in side-mode injection locked dual-mode Fabry-Pérot laser diode

“…Dual-mode laser systems have attracted considerable attention because of their numerous potential applications, including terahertz frequency generation, [1][2][3][4][5] THz imaging, 6 microwave/millimeter wave generation, [7][8][9][10] optical memory, [11][12][13][14] dual-wavelength interferometry, [15][16][17] and optical switching. 18 To date, many techniques have been proposed and experimentally demonstrated to successfully produce dual-mode lasing operation, [19][20][21][22][23][24] and among these, multi-mode Fabry-Pérot laser diode (MMFP-LD) based devices are worthy of extensive investigation because of their rich variety of nonlinear phenomena, cost effectiveness, low power consumption and low threshold current.…”

Storage ring two-color free-electron laser

“…Two spatially and temporally overlapped laser beams with two colors can be employed in coherent anti-Stokes Raman spectroscopy to study molecular vibrations through nonlinear interactions with samples [4,5]. Some other applications of multicolor lasers include excited-state spectroscopy [6,7] and photomixing processes for terahertz radiation generation [8,9]. The multicolor lasers with good collinearity are particularly important in research since the laser beams of different colors can be copropagated over a long distance, collimated and focused simultaneously.…”

Short monolithic dual-wavelength single-longitudinal-mode DBR phosphate fiber laser

“…To establish stable dualwavelength lasing at room temperature, various techniques have been employed to reduce the mode competition. These include exploiting the spatial hole burning effect in a linear cavity [13,14], utilizing two spatially separated phase-shifted DFB structures [15,16], exploiting the polarization hole burning effect by using polarization-maintaining FBGs [17][18][19][20], inserting a piece of unpumped erbium-doped fiber as a saturable absorber [21,22] and even incorporating a semiconductor optical amplifier as an inhomogenously broadened gain medium [23][24][25][26].…”