Thin Ultrafast Lenses (Plano Convex) for Femtosecond Lasers

Shalom EO’s ultrafast thin lenses are optimized with low group delay dispersion (GDD) of ±10fs2 and thin thicknesses for femtosecond pulsed lasers. In femtoline lasers, the role of lenses is to shape, direct, and manage the ultrashort pulsed laser light. Plano-convex lenses, or PCX lenses can collect and collimate divergent lights, and because of their asymmetric shape, plano-convex lens works well for conjugate ratios > 5:1. 

Generally speaking, group delay dispersion (GDD) only becomes important when the ultrafast pulse duration is down to the femtosecond scale (1fs equals 1x10^-15s) or shorter. Here’s why low GDD value and low dispersion are essential for femtosecond lasers:

1. Low GDD keeps the pulse duration short, and if the pulse is stretched, peak power will drop simultaneously

2. Temporal dispersion introduces phase distortion and decreases temporal coherence

Dispersion affects shorter pulsed ultrafast lasers more severely than longer pulse durations (such as picoseconds) because femtosecond lasers are very short in time and broad in spectrum, making them highly sensitive to wavelength-dependent delays.

Plano-convex ultrafast lenses can be used for applications like beam focusing, beam collimation, facilitating nonlinear processes, coupling pulsed lights into optical fibers or waveguides, collecting and imaging while minimizing dispersion and GDD. The lenses are suitable for multiple variations of femtosecond lasers, such as Ti:Sapphire lasers, ytterbium lasers.

Here’s a breakdown of the applications of PCX femtosecond laser lenses:

1. Beam focusing: Lenses are utilized to focus light into a tight spot. The focused laser pulses generate nonlinear harmonic generations where high peak intensities are required.

2. Beam collimation and beam shaping. Beam collimation is essential for laser applications, including femtoline lasers, as parallel light rays have minimal divergence. 

3. Ultrafast spectroscopy, where ultrashort light pulses are used to probe and monitor changes in fast dynamic processes 

Hangzhou Shalom EO provides off-the-shelf and custom plano-convex ultrafast thin lenses made of fused silica substrates and low GDD AR coatings for femtoline lasers. The standard PCX lenses feature a low GDD of ±10fs2, high profile precision (surface flatness <1/10 lambda@633nm), and are available in standardized sizes from 12.7mm to 50.8mm and focal lengths from 20mm-1000mm. Standard AR coating configurations can either be 700-900nm anti-reflection coatings for Ti: Sapphire lasers or 950-1100nm anti-reflection coatings for Yb doped lasers. In addition, plano-concave ultrafast lenses are also available in Shalom EO.

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