A tunable, singley-resonant optical parametric oscillator provides femtosecond light pulses in the infrared wavelength band. The oscillator includes an internally mounted thin crystal of KTiOPO 4 which is synchronously pumped by femtosecond pulses from a colliding-pulse passively mode-locked dye laser. Rotation of the crystal varies the wavelength of the oscillator. Prisms within the oscillator cavity control group velocity dispersion to limit pulse width, and the oscillator as stabilized by a feedback network which varies the length of the cavity in response to spectral changes.

Broadly tunable high repetition rate femtosecond optical parametric oscillator

Etude de la solvatation de composes aromatiques et des transferts de charge induisant une fluorescence double

Ultrafast Photochemical Intramolecular Charge and Excited State Solvation

A photodynamical model for the excited state electron transfer of bianthryl and related molecules

We have built a new apparatus to time resolve ultrafast fluorescence following ultraviolet excitation. A synchronously pumped dye laser produces optical pulses of 1‐ps or 70‐fs full‐width half‐maximum, depending upon dyes and optical configuration. These pulses are amplified at a 8.2‐kHz repetition rate using a copper vapor laser‐pumped multipass amplifier. The resulting amplified laser pulses are frequency doubled to obtain ultrafast pulses in the ultraviolet. This ultraviolet light is used to electronically excite a sample; the resulting fluorescence is time resolved using fluorescence upconversion as the optical gating technique. A minimum 300‐fs full‐width half‐maximum instrument response function is obtained. After a brief introduction, we discuss the principles involved in this method of time resolving fluorescence. We review special considerations for femtosecond laser experimentation, and discuss the construction of our apparatus. Finally, as an example, we show how this system can be used to stud...

Ultrafast emission spectroscopy in the ultraviolet by time‐gated upconversion

Single crystals of KTiOAsO4, a material which is isostructural with the well‐known nonlinear optical material KTiOPO4 (KTP), were grown by a flux process and its optical and dielectric properties characterized. Compared to KTP, KTiOAsO4 has a higher figure of merit for second‐harmonic generation, larger electro‐optic coefficients, and lower ionic conductivity. As a result, KTiOAsO4 should become a viable alternative for KTP.

Linear and nonlinear optical properties of flux‐grown KTiOAsO4

A hybridly mode-locked CW dye laser with brewster prisms

Optical pulses as short as 103 fsec at 695 nm and 263 fsec at 733 nm have been generated in synchronously pumped hybrid Pyridine 1 and Pyridine 2 cw dye lasers, respectively, both using the saturable absorber 1,1′-diethyl-2,2′-dicarbocyanine iodide (DDI). These results combine with other data from the same linear cavity to give direct femtosecond generation over the spectral range 560–840 nm.

Femtosecond synchronously pumped Pyridine dye lasers.

We report on the cavity-length detuning characteristics of a synchronously pumped femtosecond linear-resonator cw dye laser. The severe cavity-matching requirement (to within 0.2 μm) for optimum short-pulse generation is addressed by an active cavity-length stabilization scheme based on second-harmonic generation. This allows pulses ~100 fsec in duration to be maintained for periods of several hours.

Cavity-length detuning effects and stabilization of a synchronously pumped femtosecond linear dye laser

Optical pulses as short as 55 fs in duration have been generated near 675 nm in a synchronously pumped, hybridly mode-locked, sulforhodamine 101 dye laser. Hybrid mode locking of rhodamine B in the same cavity arrangement yielded 187 fs pulses at 650 nm.

Femtosecond pulse generation in the red/deep red spectral region

We evaluate the performance of a novel 10-Hz picosecond Nd:YAG regenerative amplifier configured as a self-filtering unstable resonator. Pulse energies of ~60 mJ in ~100 psec at 1.06 μm are achieved using a single 6-mm-diameter Nd:YAG rod, while mode-matching requirements are minimized.

Martin D. Dawson

Papers

A hybridly mode-locked CW dye laser with brewster prisms

Femtosecond synchronously pumped Pyridine dye lasers.

Cavity-length detuning effects and stabilization of a synchronously pumped femtosecond linear dye laser

Femtosecond pulse generation in the red/deep red spectral region

Characterization of a high-gain picosecond flash-lamp-pumped Nd:YAG regenerative amplifier.