arXiv subjects

Shai Yefet

Publications and source records attributed to Shai Yefet.

5 recordsLinked to original sources

arXiv2016

Dispersion Compensation using a Prism-pair

A simple and intuitive formulation is reviewed for the Brewster prism-pair - A most common component in spectroscopy-oriented experiments using ultrashort pulses. This review aims to provide students and beginners in the field of spectroscopy with a unified description of a major experimental component. The total spectral phase experienced by a broadband light field is calculated after passing through a pair of Brewster-cut prisms, demonstrating the flexibility of the prism pair to provide tuned, low-loss control of the dispersion and spectral phase experienced by ultrashort pulses

physics.optics↗

arXiv2015

Octave-Spanning Phase Control for Single-Cycle Bi-Photons

The quantum correlation of octave-spanning time-energy entangled bi-photons can be as short as a single optical cycle. Many experiments designed to explore and exploit this correlation require a uniform spectral phase (transform-limited) with very low loss. So far, transform-limited single-cycle bi-photons were not demonstrated, primarily due to lack of precision control of the spectral phase. Here, we demonstrate precise correction of the spectral-phase of near-octave bi-photons to less than ($<π/20$) (residual phase) over nearly a full octave in frequency ($\approx1330-2600$ nm). Using a prism-pair with an effectively-negative separation, we obtain tuned, very low-loss compensation of both the 2nd and 4th dispersion orders. We verify the bi-photons spectral phase directly, using a non-classical bi-photon interference effect.

physics.optics↗

arXiv2015

A Review of Cavity Design for Kerr Lens Mode-Locked Solid-State Lasers

We provide a critical review of the fundamental concepts of Kerr lens mode-locking (KLM), along with a detailed description of the experimental considerations involved in the realization of a mode-locked oscillator. In addition, we review recent developments that overcome inherent limitations and disadvantages in standard KLM lasers. Our review is aimed mainly at readers who wish to realize/maintain such an oscillator or for those who wish to better understand this major experimental tool.

physics.optics↗

arXiv2015

Intra-cavity gain shaping of mode-locked Ti:Sapphire laser oscillations

The gain properties of an oscillator strongly affect its behavior. When the gain is homogeneous, different modes compete for gain resources in a `winner takes all' manner, whereas with inhomogeneous gain, modes can coexist if they utilize different gain resources. We demonstrate precise control over the mode competition in a mode locked Ti:sapphire oscillator by manipulation and spectral shaping of the gain properties, thus steering the competition towards a desired, otherwise inaccessible, oscillation. Specifically, by adding a small amount of spectrally shaped inhomogeneous gain to the standard homogeneous gain oscillator, we selectively enhance a desired two-color oscillation, which is inherently unstable to mode competition and could not exist in a purely homogeneous gain oscillator. By tuning the parameters of the additional inhomogeneous gain we flexibly control the center wavelengths, relative intensities and widths of the two colors.

physics.optics↗

arXiv2013

Mode Locking At and Below the CW Threshold

We explore experimentally a new regime of operation for mode locking in a Ti:Sapphire laser with enhanced Kerr nonlinearity, where the threshold for pulsed operation is lowered below the threshold for continuous-wave (CW) operation. Even though a CW solution cannot exist in this regime, pulsed oscillation can be realized directly from zero CW oscillation. In this regime, the point of maximum strength of the Kerr nonlinear process provides a "sweet spot" for mode locking, which can be optimized to considerably lower the pump power threshold. The properties of the "sweet spot" are explained with a qualitative model.

physics.optics↗