Pump-probe phase spectroscopy with submilliradian sensitivity and nanosecond time delay using Michelson...

Area of Science:

• Physical Chemistry
• Spectroscopy
• Materials Science

Background:

• Pump-probe spectral interferometry is crucial for studying ultrafast dynamics.
• Traditional Sagnac interferometer methods face limitations with long time delays, requiring large setups and potentially introducing artifacts from long-lived sample effects.

Purpose of the Study:

• To present a new experimental scheme for sensitive pump-probe spectral interferometry at long time delays.
• To offer practical advantages over existing Sagnac interferometer techniques.
• To demonstrate the versatility of the new method through specific applications.

Main Methods:

• Utilized a double Michelson interferometer setup.
• Achieved spatial separation of probe and reference pulses at the sample.
• Enabled straightforward production and continuous adjustment of fixed delays while maintaining alignment.

Main Results:

• Successfully measured transient phase spectra in a thin tetracene film with up to 5 ns probe delay.
• Performed impulsive stimulated Raman measurements in Bi4Ge3O12.
• Demonstrated comparable signal-to-noise ratios to existing methods with the advantage of arbitrarily long pump-probe time delays.

Conclusions:

• The double Michelson interferometer scheme provides a practical and sensitive method for pump-probe spectral interferometry at long time delays.
• The spatial separation of pulses alleviates issues associated with long-lived sample effects.
• This technique offers flexibility and improved performance for various spectroscopic applications.