Carrier-envelope Phase Fluctuation Research Articles

Carrier-envelope phase offset for pulses from a tunable optical parametric amplifier

The carrier-envelope phase (CEP) characteristics of the tunable infrared laser pulses from a noncollinear optical parametric amplifier (OPA) with passively stabilized CEP are investigated experimentally. We compare the CEP fluctuation of different wavelength outputs from the OPA which is seeded by the idler pulse of a difference frequency generation (DFG) process. It is found that when the OPA output is tuned to a longer wavelength, the CEP fluctuation becomes less sensitive to the jitter of laser intensity and the phase mismatch, and therefore more stable CEP for the longer wavelength output pulses is realized.

Carrier-envelope stabilized few-cycle infrared laser system

According to the feature of the passive carrier-envelope phase (CEP) stabilized idler of the optical parametric amplified process, a CEP stabilized three-stage collinear optical parametric amplifier is built. Millijoule ultrashort infrared output (1.4 mJ/40 fs/1 kHz at 1.8 μm) with CEP fluctuation ~516mrad is obtained from the system. After passing through a hollow-core fiber and block material, the pulses are finally compressed to less than two cycles (<12 fs), and the single pulse energy is 0.54mJ. The system provides an excellent laser source for the experiments of individual attosecond pulse generation and other high harmonic generation (HHG).

Tunable phase-stabilized infrared parametric laser source

This paper reports that the tunable self-phase-stabilized infrared laser pulses have been generated from a two-stage optical parametric amplifier. With an 800 nm pump source, the output idler pulses are tunable from 1.3μm to 2.3μm, and the maximum output energy of the idler pulses is higher than 1 mJ at 1.6μm by using 6 mJ pump laser. A carrier-envelope phase fluctuation of ∼0.15 rad (rms) for the idler pulses is measured for longer than one hour by using a home build f-to-2f interferometer.

Measurement of the carrier-envelope phase stability of infrared femtosecond laser pulses by two-path interferometer

We describe a self-referencing two-path interferometer designed to measure the carrier-envelope phase stability. In experiment, we measure the carrier-envelope phase （CEP） stability of a home-made infrared tunable OPA laser pulses with the self-referencing two-path interferometer. When the wavelength of the incident pulses is 1.6 μm, the CEP fluctuation is 115 mrad （rms） in 100 seconds. The interferometer can provide an accurate and quick measurement of the pulse CEP.

Carrier-envelope phase stabilization of high-contrast femtosecond laser pulses with a relativistic intensity

We report on the generation of carrier-envelope phase (CEP)-stabilized pulses with a relativistic intensity and a high-contrast ratio. The CEP stabilization is achieved with a jitter of 0.95rad from a 0.5kHz femtosecond laser pulses with a focal intensity of 2.6×1018W∕cm2 and a picosecond contrast of 2.5×10−9. CEP noise analysis shows that the beam pointing at the pulse compressor is a dominant factor of the CEP fluctuation with our laser system.

Fluctuation of the Carrier-Envelope Phase of a Few-Cycle Laser Pulse from a Chirped-Pulse Amplification System with the Gas Pressure in a Hollow Fiber

We experimentally confirmed that additional CEP fluctuations induced in a hollow fiber increased with gas pressure. A gas pressure in the hollow fiber of between 2 and 2.5 atm results in both a short-pulse generation and the small CEP fluctuation. We also measured the carrier-envelope phase (CEP) fluctuations of spectrally broadened intense pulses that passed through a hollow fiber. An additional carrier-envelope phase fluctuation of 0.12 rad was induced in white light generated in the hollow fiber under the optimum gas pressure.

Self-stabilization of the carrier-envelope phase of an optical parametric amplifier verified with a photonic crystal fiber.

Experimental verification is given for self-stabilization of the carrier-envelope phase (CEP) of idler pulses from a noncollinear optical parametric amplifier. The verification is performed by spectral interference (SI) between an octave-broadened supercontinuum (SC) and its second harmonic. This SC is generated by nonlinear propagation of the second harmonic of the idler through a photonic crystal fiber (PCF). Although the modulational instability causes the intensity and CEP fluctuation and the amplified spontaneous emission noise in PCF degrades the visibility of SI, the CEP is verified to be stabilized.

Measurements of carrier-envelope phase changes of 100-Hz amplified laser pulses

We report measurements of the carrier-envelope phase (CEP) changes of 100-Hz amplified laser pulses through observation of the spectral interference between a white-light continuum generated by the self-phase modulation and its second harmonic (SH). The fluctuation of the time delay between the fundamental and the SH, which would be caused by the intensity fluctuation of the pulse, was excluded by deriving the time delay and the phase independently. The CEP slip of the amplified pulses showed a random distribution, which would be mainly due to the fluctuation of the uncontrolled oscillator. Effects of the amplification system on the CEP fluctuation are also discussed.