Subpicosecond Pulse Generation Research Articles

Subpicosecond-pulse generation in a synchronously mode-locked ring color-center laser

Data are presented for the operation of a versatile color-center laser that permitted the generation of stable trains of subpicosecond pulses in a synchronously pumped ring configuration. With LiF:F(2)(+) as the gain medium, pulses having durations of 0.7 psec (Gaussian pulse shape assumed) were reliably obtained with average powers of 15-20 mW available in each of the two output beams. These pulse widths are more than a factor of 2 shorter than those obtained when this laser was configured with a standing-wave resonator.

Generation of 320 fs pulses with a distributed feedback dye laser

A new achromatic distributed feedback dye laser (DFDL) arrangement is described. The experimental conditions for subpicosecond pulse generation with the new device were investigated. For the first time, stable generation of subpicosecond pulses (τ≦350 fs) at 616 nm was achieved with a DFDL. The simultaneous spectral and autocorrelation measurements showed that the amplified DFDL pulses are nearly transform limited, having a pulse form close to the sech2 shape.

Generation and amplification of subpicosecond ultraviolet radiation pulses in excimer lasers

Subpicosecond (350 fsec) high-power (6 GW) ultraviolet radiation (308 nm) pulses were generated using a specially developed system. The energy obtained from an excimer amplifier operating in the saturation regime was found to increase because of the broadening of the spectrum of the amplified signal when femtosecond pulses were generated.

Generation of subpicosecond solitonlike optical pulses at 0.3 THz repetition rate by induced modulational instability

We report the generation of 0.5 ps full width at half-maximum optical pulses at >0.3 THz (tunable) repetition rate via an induced modulational instability in a single-mode fiber. A 1.319-μm neodymium:yttrium aluminum garnet laser is chosen as the carrier wave and the initial modulation on this carrier is introduced by mixing it with an external-grating-cavity InGaAsP laser. The use of this all-optical modulating scheme and the nonlinear optical propagation effect in fiber (i.e., modulational instability) allows one to reach into the terahertz regime, which is about two orders of magnitude beyond the fastest data limited by the finite response of electronics.

Generation of high peak power subpicosecond pulses in the 1.0–1.6 μm range by parametric amplification in an organic crystal

High peak power subpicosecond optical pulses have been generated by parametric amplification of a white-light femtosecond continuum in a new organic crystal, N-(4-nitrophenyl)-L-prolinol or (NPP), with an emission spectrum extending in the 1.0–1.6 μm range.

The passive modelocking of the continuous wave Rhodamine B dye laser

The passive modelocking of a cw rhodamine B dye laser is reported. In a simple linear cavity with no dispersion correction, subpicosecond pulse generation was achieved over the spectral range 616–658 nm using 1,3'-diethyl-4,2'-quinolylthiacarbocyanine iodide (DQTCI) as the saturable absorber. Pulses as short as 220 fs were measured using standard second harmonic generation autocorrelation techniques.

Passively mode-locked continuous-wave Rhodamine 110 dye laser

The passive mode locking of a cw Rhodamine 110 dye laser is reported. In a simple uncompensated linear cavity, subpicosecond pulse generation was achieved over the spectral range 553–570 nm. Pulses as short as 150 fsec were recorded using standard second-harmonic autocorrelation measurement techniques. Two saturable-absorbing species were found to operate successfully in this region.

Generation of subpicosecond electrical pulses on coplanar transmission lines

Electrical pulses shorter than 0.6 ps were generated by photoconductively shorting a charged coplanar transmission line with 80 fs laser pulses. After propagating 8 mm on the line the electrical pulses broadened to only 2.6 ps.

Subpicosecond pulse generation in synchronously pumped energy transfer dye lasers

We describe the relatively efficient generation of picosecond pulses in an energy transfer dye laser synchronously pumped by an argon-ion laser and a Q-switched and modelocked cw-Nd3+: YAG laser, respectively. Maximum tuning range from 550 to 700 nm has been achieved. In both cases considerable pulse shortening in the spectral region of the donor emission was observed.

Subpicosecond pulse generation by a tandem-type AlGaAs DH laser with colliding pulse mode locking

Experimental results of colliding pulse mode locking (CPM) of a double-contact AlGaAs DH injection laser with an external cavity are presented. The laser has two amplifying sections and a passive umpumped segment located between them which exhibited saturable absorption action. Ultrashort pulses propagating in opposite directions collided in the absorber and pulse shortening occurred. Bursts of 0.8 ps (FWHM) pulses at a 710 MHz repetition rate are obtained by means of CPM. The pulse duration is measured by a second harmonic generation correlation method and an ultrafast streak camera.

Generation of subpicosecond pulses from a continuous-wave mode-locked Nd:YAG laser using a two-stage optical compression technique

By using a two-stage optical-fiber grating pair pulse-compression technique, 1.06-microm pulses as short as 0.7 psec have been obtained from an actively mode-locked cw Nd:YAG laser. This represents an overall pulse-compression ratio of 113.

Subpicosecond pulse generation in a branched passively mode-locked Nd-glass laser

A two-branch passively mode-locked Nd-glass laser is applied to generate light pulses down to 0.4 ps duration (average duration 0.9 ps). The laser action is initiated in a path of high saturable dye transmission and then switched to a branch of low saturable dye transmission for efficient pulse compression. The experimental results are compared with computer simulations.

1 GW high power subpicosecond pulse generation in near IR region

A tunable high power subpicosecond pulse laser with a peak power of more than 1 GW, pulse width of 0.8 ps in the near IR region has been realized. Details of the characteristics of the amplified spontaneous emission and amplification of the laser light in this system are described.

Generation of subpicosecond continuously frequency-tunable infrared pulses

An investigation was made of a cavity optical parametric oscillator (COPO) utilizing a KDP crystal pumped synchronously with the second harmonic of a picosecond neodymium phosphate glass laser with passive mode locking. A strong discrimination of the time profile of the signal under conditions of gain saturation and group velocity mismatch resulted in generation of subpicosecond pulses (~0.5 psec) in the COPO when the duration of the pump pulses was 3–5 psec. The COPO was tunable in the range 0.82–1.3 μ, the energy efficiency of the conversion process was 2%, and the average energy of a single subpicosecond pulse was 20 μ J. A numerical analysis was made of the transient parametric amplification in the COPO and the subpicosecond COPO was optimized so as to reduce the pulse duration and increase their contrast.

High-power, subpicosecond 10-μm pulse generation

Two-picosecond, 10-microm pulses, generated by optical semiconductor switching, have been regeneratively amplified in a multiatmosphere TE CO(2) gain module. Pulses have been produced with a peal circulating energy of ~15 mJ and a power density in the gain medium in excess of 10(12) W/cm(2). A plasma-breakdown wave, traveling with the regeneratively amplified pulse, combined with anomalous dispersion in the NaCl windows, has permitted compression of these pulses to less than 1 psec in duration.

Generation, stabilization, and amplification of subpicosecond pulses

A sync-pumped cw dye laser system has been used to produce subpicosecond pulses. Pulses as short as 0.7 ps, assuming a single-sided exponential pulse shape, were observed. A set of experiments was performed to investigate the origin and effects of noise in the sync-pumped system. A digital and an analog feedback loop have been designed to optimize the pulse width. The noise has been lowered by 10 dB for frequencies up to 10 kHz; long-term drift is also controlled by this method. A four-stage dye laser amplifier, pumped by a Nd:YAG laser which operates at a 10-Hz repetition rate, is synchronized electronically to the dye-laser picosecond pulses. A gain of 3×106 has been achieved.

High-Power Subpicosecond Pulse Generation in Near-IR Region by Cavity-Dumped Passive and Synchronous Hybrid Mode-Locking System

High-Power Subpicosecond Pulse Generation in Near-IR Region by Cavity-Dumped Passive and Synchronous Hybrid Mode-Locking System

Generation of subpicosecond coherent optical pulses by passive mode locking of an AlGaAs diode laser

Subpicosecond coherent optical pulses as short as 0.58 ps were generated for the first time by passive mode locking of an AlGaAs double heterostructure diode laser. It was realized by a simple configuration made of a conventional AlGaAs diode laser without antireflection coatings on both facets, which was aged and exhibiting self-pulsation, placed in an external cavity. When the external cavity length was shorter than about 60 mm, almost complete mode locking was observed over the oscillation spectrum of 3.5 nm in width. Based on the second-harmonic generation autocorrelation measurement, ultrashort coherent optical pulses from 0.58 to 1.2 ps in duration were demonstrated by increasing the external cavity length together with the proper control of the optical feedback effect and the pumping dc current.

Generation of subpicosecond pulses from an actively mode locked GaAs laser in an external ring cavity

We report the active mode locking of the emission from a GaAs buried optical guide laser in an external ring cavity. The two counter rotating pulses interact in the laser which in addition to the gain medium contains a saturable absorber at one facet introduced by proton bombardment at 600 keV with a 3×1015 cm−2 dosage level. Bursts of pulses with 0.56 psec FWHM at a 625-MHz repetition rates have been obtained.

Subpicosecond pulse generation in a synchronously mode-locked bidirectional ring laser

Subpicosecond pulse generation in a synchronously mode-locked bidirectional ring laser