COMBINED MIR AND THZ OPTICAL GRATING FOR VERTICAL THZ EMISSION IN DFG-QCLS

摘要

A light source for generating light of a predefined wavelength, comprising a waveguide structure (10) defining a propagation direction of light, wherein said waveguide structure (10) comprises an active region (12) comprising a gain medium for amplifying light within said waveguide structure (10), and a non-linear medium suitable for generating light of the predefined wavelength from light of a first wavelength and from light of a second wavelength by means of difference frequency generation or sum frequency generation. The waveguide structure (10) further comprises a first optical grating (14) and a second optical grating (16). The first optical grating (14) is configured to ensure lasing of the first wavelength and of the second wavelength and to suppress lasing at any other wavelength to thereby generate light of said first wavelength and light of said second wavelength, wherein said first optical grating (14) is further configured to determine a first spatial phase relationship of the light of the first wavelength, and a second spatial phase relationship of the light of the second wavelength. The second optical grating (16) is configured for extracting light of the predefined wavelength out of the waveguide structure (10) in an extraction direction substantially perpendicular to the propagation direction, wherein the second optical grating (16) is arranged relative to the first optical grating (14) such that a constructive interference of the light of said predefined wavelength in the far field is provided.