Laser device (100) comprising: - a substrate (10) on the surface of which an optical
waveguide (11) is arranged, which contains an optical
resonator (12, 13) with a
resonator length such that at least one
resonator mode in the resonator (12, 13) forms a
standing wave, and - a
gain medium arranged on a surface of the optical
waveguide (11) and comprising a plurality of
semiconductor elements (21) arranged periodically on the surface of the optical
waveguide (11) in a manner projecting from the optical waveguide (11), wherein: - the
gain medium is arranged for
optical interaction with the at least one
resonator mode of the optical resonator (12, 13) and for amplifying light having a
wavelength of the at least one
resonator mode of the optical resonator (12, 13), - the
gain medium comprises a
photonic crystal (20) and the
semiconductor elements (21) are columnar and / or wall-shaped
semiconductor elements (21), and - a diffractive
coupling is formed between the
photonic crystal (20) and the optical resonator (12, 13), in which standing light
waves in the optical resonator (12, 13) are extended to the
photonic crystal (20), characterized in that - a periodicity of the arrangement of the semiconductor elements (21) defines a
coupling wavelength which is coupled between the semiconductor elements (21) and the waveguide (11), wherein the
coupling wavelength and a
resonance wavelength defined by the resonator length of the optical resonator (12, 13) are simultaneously selected such that the
resonance wavelength in the waveguide (11) matches the coupling wavelength.