Colliding-pulse Mode-locked Ring Dye Research Articles

Femtosecond pulses generated from non-colliding pulse mode- locked ring dye lasers

Optical pulses shorter than 50 fs have been directly generated from non-colliding pulse mode-locked ring dye lasers with a four- prism sequence. This result supports the view that the balance between the self-phase modulation and the group velocity dispersion inside the cavity, and the greater flexibility of the ring cavity over the standing wave cavity, are the main factors in obtaining femtosecond pulses from the colliding pulse mode-locked ring dye lasers.

Generation of 49 fs pulses in a CPM laser pumped by a small-frame Ar+ laser

A colliding pulse mode-locked ring dye laser, pumped by an all-line small frame Ar+ laser has been used to generate stable pulses as short as 49 fs with pulse duration and stability similar to those obtained with the usual configuration where a single line of the pump is used. The effects of cavity alignment on the absorber saturation are presented and explained in terms of an analysis of stability of the ring cavity.

Characteristics of Femtosecond Pulses from a Colliding Pulse Mode-Locked Ring Dye Laser

A colliding pulse mode-locked ring dye laser generating 88-fs pulses has been constructed. To produce the shortest pulse duration, the optimum condition concerning with the curvature of mirrors, the slit-width of the jet nozzle, pressure and concentration for a saturable absorber is discussed. In addition, fluctuations of the pulse-repetition rate are experimentally investigated in detail. As a result, it is shown that there are basically two types of fluctuation: jitter and drift, of which main reasons are vibration of the jet stream of saturable absorber and temperature dependence of the cavity length.

Microcomputer-based spectrum-resolved second-harmonic generation correlator for fast measurement of ultrashort pulses

A new spectrum-resolved second-harmonic generation correlator using a single-line image sensor array and a microcomputer has been developed. It allows us acquisition of many spectrum-resolved second-harmonic generation correlation traces in a single scan of the optical delay. Using this correlator, the pulse properties of a colliding pulse mode-locked ring dye laser have been investigated. It was found that the measuring time can be reduced by an order of magnitude compared with the conventional repeat-scan method.

Femtosecond excited state relaxation of dye molecules in solution

The bleaching dynamics of organic dye molecules in solution have been investigated using 70 fs pulses from a colliding pulse mode-locked ring dye laser. In addition to ground state relaxation on a nanosecond time scale, a fast partial recovery is observed. For the dyes Nile blue, oxazine 720, cresyl violet and rhodamine 640, this recovery is exponential, with relaxation times in the range 190–480 fs.