R. Jason Jones

Broadband Cavity Ringdown Spectroscopy for Sensitive and Rapid Molecular Detection

We demonstrate highly efficient cavity ringdown spectroscopy in which a broad-bandwidth optical frequency comb is coherently coupled to a high-finesse optical cavity that acts as the sample chamber. 125,000 optical comb components, each coupled into a specific longitudinal cavity mode, undergo ringdown decays when the cavity input is shut off. Sensitive intracavity absorption information is simultaneously available across 100 nanometers in the visible and near-infrared spectral regions. Real-time, quantitative measurements were made of the trace presence, the transition strengths and linewidths, and the population redistributions due to collisions and the temperature changes for molecules such as C2H2, O2, H2O, and NH3.

Delivery of high stability optical and microwave frequency standards over an optical fiber network

Optical and radio frequency standards located in JILA and National Institute of Standards and Technology (NIST) laboratories have been connected through a 3.45-km optical fiber link. An optical frequency standard based on an iodine-stabilized Nd:YAG laser at 1064 nm (with an instability of ∼4×10-14 at 1 s) has been transferred from JILA to NIST and simultaneously measured in both laboratories. In parallel, a hydrogen maser-based radio frequency standard (with an instability of ∼2.4×10-13 at 1 s) is transferred from NIST to JILA. Comparison between these frequency standards is made possible by the use of femtosecond frequency combs in both laboratories. The degradation of the optical and rf standards that are due to the instability in the transmission channel has been measured. Active noise cancellation is demonstrated to improve the transfer stability of the fiber link.

Mode-locked fiber laser frequency-controlled with an intracavity electro-optic modulator

We demonstrate a mode-locked, erbium-doped fiber laser with its repetition frequency synchronized to a second fiber laser via an intracavity electro-optic modulator (EOM). With servo control from the EOM (bandwidth approximately 230 kHz) and a slower speed intracavity piezoelectric transducer (resonance at approximately 20 kHz), we demonstrate stabilization of the repetition frequency with an in-loop rms timing jitter of 10 fs, integrated over a bandwidth from 1 Hz to 100 kHz. This represents what is to our knowledge the first time an EOM has been introduced inside a mode-locked laser cavity for fast servo action and the lowest timing jitter reported for a mode-locked fiber laser.

Femtosecond pulse amplification by coherent addition in a passive optical cavity

By simultaneously controlling repetition and carrier frequencies, one can achieve the phase coherent superposition of a collection of successive pulses from a mode-locked laser. An optical cavity can be used for coherent delay and constructive interference of sequential pulses until a cavity dump is enabled to switch out the amplified pulse. This approach will lead to an effective amplification process through decimation of the original pulse rate while the overall coherence from the oscillator is preserved. Detailed calculations show the limiting effects of intracavity dispersion and indicate that enhancement of sub-100-fs pulses to microjoule energies is experimentally feasible.

Picosecond-pulse amplification with an external passive optical cavity

We experimentally demonstrate the amplification of picosecond pulses at high repetition rates through the coherent addition of successive pulses of a mode-locked pulse train in a high-finesse optical cavity equipped with cavity dumping. Amplification greater than 30 times is obtained at a repetition rate of 253 kHz, boosting the 5.3-nJ pulses from a commercial mode-locked picosecond Ti:sapphire laser to pulse energies of more than 150 nJ.

Applications of Ultrafast Lasers

We discuss implementations of mode-locked ring lasers, their stabilization via passive optical cavities, and their applications to the development of ultrasensitive sensors.

Passive optical amplifier for picosecond and fenitosecond pulses

The coherent superposition of mode-locked pulses stored in a passive optical cavity results in a single amplified pulse when switched out. Theoretical and experimental results demonstrate superior performance when compared with active cavity dumping techniques.The coherent superposition of mode-locked pulses stored in a passive optical cavity results in a single amplified pulse when switched out. Theoretical and experimental results demonstrate superior performance when compared with active cavity dumping techniques.

Precise phase control of short pulses

Summary form only given. We will discuss the strong impact of precision phase control of optical pulses to fields ranging from ultrafast science Io precision metrology.

Pump-Probe Intracavity Phase Spectroscopy

Pump-probe intracavity phase spectroscopy utilizes a femtosecond enhancement cavity to enable precision measurements of high-field ultrafast nonlinearites. We demonstrate this new approach measuring the pump-induced plasma evolution of a xenon target with a time-delayed probe.

High Power Femtosecond Frequency Comb for Intracavity High Harmonic Generation

We report on a high power (~6.5 Watts) Ti:sapphire based frequency comb (50MHz) generating ~25 microjoule pulses inside an enhancement cavity. Intracavity high-harmonic generation produces over 2.5 microwatts integrated power from 73 to 53 nm.