We outline a simple laser cavity comprising an opaque ring and a circular aperture that is capable of producing spatially tuneable laser modes, from a Gaussian beam to a Flat-top beam. The tuneability is achieved by varying the diameter of the aperture and thus requires no realignment of the cavity. We demonstrate this principle using a digital laser with an intra-cavity spatial light modulator...

Resonator-based optical sensors detect the change of refractive index in the environment by measuring the resonance shift. The sensitivity of such sensors is determined by how precise one can locate the resonant wavelength, which is thought to be limited by the bandwidth and the quality factor of the resonator. Here we show that, with a tunable resonator, one can determine the resonant waveleng...

We investigate experimentally and theoretically the dynamics of a capacitive resonator under mixed frequency excitation of two AC harmonic signals. The resonator is composed of a proof mass suspended by two cantilever beams. Experimental measurements are conducted using a laser Doppler Vibrometer to reveal the interesting dynamics of the system when subjected to twosource excitation. A nonlinea...

We numerically investigate the properties of a hybrid grating structure acting as a resonator with ultrahigh quality factor. This reveals that the physical mechanism responsible for the resonance is quite different from the conventional guided mode resonance (GMR). The hybrid grating consists of a subwavelength grating layer and an un-patterned high-refractive-index cap layer, being surrounded ...

The linewidth of a KGd(WO ₄) ₂ (KGW) intracavity pumped Raman laser is analyzed experimentally for different configurations of the Raman and pump laser resonators: with narrow and broadband pump emission profiles, with and without linewidth narrowing elements in the Raman laser resonator, with and without injection seeding into the Raman cavity. The benefits of a narrow linewidth pump source in...

A prismless ultrafast Cr4*:YAG laser has been designed and constructed. Intracavity dispersion in this laser is compensated through the use of double-chirped mirrors, in contrast to previous work, which used fused silica prisms. The resonator design for Kerr lens modelocking has been optimized through the use of numerical simulation programs, based on the ABCD transfer matrix formalism. Pulses ...

We experimentally present a three-mirror folded singly resonant sum-frequency generation (SFG) cavity with an adjustable input coupling, which has been applied to 520-nm single-frequency laser generation via 780-nm laser and 1560-nm laser frequency mixing in a periodically poled KTiOPO4 crystal (PPKTP). A continuous variation in the input coupling reflectivity from 81.4 to 96.1% for 780-nm reso...

We have demonstrated semiconductor lasers with microring resonators as frequency-selective elements. We show that the small resonator inside the laser makes single frequency-mode operation possible with reasonably good side-mode rejection.