An experimental apparatus is described for multidimensional optical spectroscopy with fully automated polarization control, based on liquid crystal variable retarders. Polarization dependence of rephasing two-dimensional coherent spectra are measured in a single scan, with absolute phasing performed for all polarization configurations through a single automated auxiliary measurement at the beginning of the scan. A factor of three improvement in acquisition time is demonstrated, compared to the apparatus without automated polarization control. Results are presented for a GaAs quantum well sample and an InGaAs quantum well embedded in a microcavity.An experimental apparatus is described for multidimensional optical spectroscopy with fully automated polarization control, based on liquid crystal variable retarders. Polarization dependence of rephasing two-dimensional coherent spectra are measured in a single scan, with absolute phasing performed for all polarization configurations through a single automated auxiliary measurement at the beginning of the scan. A factor of three improvement in acquisition time is demonstrated, compared to the apparatus without automated polarization control. Results are presented for a GaAs quantum well sample and an InGaAs quantum well embedded in a microcavity.

Optics ExpressOct 17, 20197 citations

Knob of adjusting transient optical switching by an outer magnetic field in a V-type degenerate medium

Thanh Thai Doan, Hoang Minh Dong

Abstract Magnetic field plays an important role in studying the transient response because the transition probabilities of degenerate energy levels depend on the external field. The application of an external magnetic field is of particular interest, as the magnetic field is readily available and more flexible to control than an additional laser field, which is an essential consideration in our paper. In this work, we propose a simple model for managing the transient absorption and dispersion properties in a degenerate two-level atomic medium under both transparency and absorption regimes in the presence of spontaneously generated coherence (SGC), an incoherent pumping field, and an external magnetic field. We show that a magnetic field can be utilized as a ‘knob’ to swap the transient absorption and dispersion properties of the system in both transparency and absorption regimes. The magnetic field not only aids in creating transparency and absorption regimes but is also helpful in controlling the system operating at different frequency regions for the probe field without changing the frequency of the coupling field; SGC is introduced to enhance the laser phase dependence of the atomic optical properties, while the incoherent pumping field plays a role in enhancing the effects of SGC and relative phase on the atomic optical properties. The influences of SGC, relative phase, and incoherent pumping rate on transient response are also considered to improve the stability of transient absorption and dispersion properties. Moreover, the essential time required for swapping between subluminal and superluminal light propagation is also provided. The proposed model shows that the system can be used as an ultrafast optical switch, which, in practice, may enable control over switching rates in quantum storage and information-processing devices.Abstract Magnetic field plays an important role in studying the transient response because the transition probabilities of degenerate energy levels depend on the external field. The application of an external magnetic field is of particular interest, as the magnetic field is readily available and more flexible to control than an additional laser field, which is an essential consideration in our paper. In this work, we propose a simple model for managing the transient absorption and dispersion properties in a degenerate two-level atomic medium under both transparency and absorption regimes in the presence of spontaneously generated coherence (SGC), an incoherent pumping field, and an external magnetic field. We show that a magnetic field can be utilized as a ‘knob’ to swap the transient absorption and dispersion properties of the system in both transparency and absorption regimes. The magnetic field not only aids in creating transparency and absorption regimes but is also helpful in controlling the system operating at different frequency regions for the probe field without changing the frequency of the coupling field; SGC is introduced to enhance the laser phase dependence of the atomic optical properties, while the incoherent pumping field plays a role in enhancing the effects of SGC and relative phase on the atomic optical properties. The influences of SGC, relative phase, and incoherent pumping rate on transient response are also considered to improve the stability of transient absorption and dispersion properties. Moreover, the essential time required for swapping between subluminal and superluminal light propagation is also provided. The proposed model shows that the system can be used as an ultrafast optical switch, which, in practice, may enable control over switching rates in quantum storage and information-processing devices.

Journal of OpticsSep 1, 20260 citations

CAVITY-ENHANCED ULTRAFAST TRANSIENT ABSORPTION SPECTROSCOPY

Yuning Chen, Thomas G. Allison, Kevin Keleher +1 more

We introduce cavity enhanced ultrafast transient absorption spectroscopy, which employs frequency combs and high-finesse optical cavities. % The schematic of apparatus is shown in Figure 1. Sub-100 fs pulses with a repetition rate of 90 MHz are generated by a home-built Ytterbium fiber laser. The amplified light has a power up to 10 W, which is used to pump an optical parametric oscillator, followed by second-harmonic generation(SHG) that converts the wavelength from near-IR to visible. A pump comb at 530 nm is separately generated by SHG. Both pump and probe combs are coupled into high-finesse cavities. Compared to the conventional transient absorption spectroscopy method, the detection sensitivity can be improved by a factor of $\left(\frac{\mathcal{F}}{\pi} \right)^2 \sim 10^5$ , where $\mathcal{F}$ is the finesse of cavity. This ultrasensitive technology enables the direct all-optical dynamics study in molecular beams. We will apply the cavity enhanced ultrafast transient absorption spectroscopy to investigate the dynamics of visible chromophores and then extend the wavelength to mid-IR to study vibrational dynamics of small hydrogen-bonded clusters. %\begin{wrapfigure}{I}{1\textwidth} % \centering % \includegraphics[width = 0.7\textwidth]{CETAS_details.eps} %\caption{Schematic of cavity enhanced ultrafast transient absorption spectroscopy apparatus. An amplified fiber laser frequency comb is converted to visible light and pump and probe combs are coupled to high-finesse optical resonators. Transmission of the probe light is measured.} %\end{wrapfigure}We introduce cavity enhanced ultrafast transient absorption spectroscopy, which employs frequency combs and high-finesse optical cavities. % The schematic of apparatus is shown in Figure 1. Sub-100 fs pulses with a repetition rate of 90 MHz are generated by a home-built Ytterbium fiber laser. The amplified light has a power up to 10 W, which is used to pump an optical parametric oscillator, followed by second-harmonic generation(SHG) that converts the wavelength from near-IR to visible. A pump comb at 530 nm is separately generated by SHG. Both pump and probe combs are coupled into high-finesse cavities. Compared to the conventional transient absorption spectroscopy method, the detection sensitivity can be improved by a factor of $\left(\frac{\mathcal{F}}{\pi} \right)^2 \sim 10^5$, where $\mathcal{F}$ is the finesse of cavity. This ultrasensitive technology enables the direct all-optical dynamics study in molecular beams. We will apply the cavity enhanced ultrafast transient absorption spectroscopy to investigate the dynamics of visible chromophores and then extend the wavelength to mid-IR to study vibrational dynamics of small hydrogen-bonded clusters. %\begin{wrapfigure}{I}{1\textwidth} % \centering % \includegraphics[width = 0.7\textwidth]{CETAS_details.eps} %\caption{Schematic of cavity enhanced ultrafast transient absorption spectroscopy apparatus. An amplified fiber laser frequency comb is converted to visible light and pump and probe combs are coupled to high-finesse optical resonators. Transmission of the probe light is measured.} %\end{wrapfigure}

International Symposium on Molecular Spectroscopy (ISMS)Jun 16, 20140 citations

OPTICAL COHERENT TRANSIENTS

M. D. Levenson

Elsevier eBooksJan 1, 19820 citations

\left(\frac{\mathcal{F}}{\pi} \right)^2 \sim 10^5

, where

\mathcal{F}

is the finesse of cavity. This ultrasensitive technology enables the direct all-optical dynamics study in molecular beams. We will apply the cavity enhanced ultrafast transient absorption spectroscopy to investigate the dynamics of visible chromophores and then extend the wavelength to mid-IR to study vibrational dynamics of small hydrogen-bonded clusters. %\begin{wrapfigure}{I}{1\textwidth} % \centering % \includegraphics[width = 0.7\textwidth]{CETAS_details.eps} %\caption{Schematic of cavity enhanced ultrafast transient absorption spectroscopy apparatus. An amplified fiber laser frequency comb is converted to visible light and pump and probe combs are coupled to high-finesse optical resonators. Transmission of the probe light is measured.} %\end{wrapfigure}