Low-aberration high-speed-compatible optical delay line.

Area of Science:

• Optical Engineering
• Spectroscopy
• Physics

Background:

• Optical delay lines are crucial for time-resolved measurements.
• Aberrations in delay lines limit spectral resolution and signal fidelity.
• Existing designs often struggle with dispersion and aberrations over extended delay ranges.

Purpose of the Study:

• To present a new, simple design for dispersion-free optical delay lines.
• To minimize wavefront aberrations for improved optical system performance.
• To enhance spectral resolution in Fourier transform coherent anti-Stokes Raman scattering (FT-CARS).

Main Methods:

• Designed an optical delay line incorporating a line of symmetry to guide non-axial beam displacements.
• Minimized optical aberrations by aligning beam paths along this symmetry axis.
• Compared simulation and experimental results with a conventional delay line lacking this feature.

Main Results:

• The new design significantly reduced wavefront aberrations compared to a similar delay line without a line of symmetry.
• Demonstrated improved performance and transform-limited spectral resolution recovery.
• Achieved 3.5 cm⁻¹ spectral resolution over a 10 ps delay scan range.

Conclusions:

• The proposed simple optical delay line design effectively minimizes aberrations.
• This design enables high spectral resolution in time-resolved spectroscopic techniques like FT-CARS.
• The findings facilitate more precise measurements in various scientific applications.