Usually, it's difficult for us to observe the Compton Scattering in an atom. One way to overcome this difficult is using multi-photon collide with an atom, which will come into being multi-photon Compton Scattering (MCS) phenomenon. Thus, we can investigate the MCS process in visible light region. During the MCS process, the cluster atoms moving as a whole, namely atomic Dicke states, the multi-photon interacting with cluster atoms. We can observe a significant Doppler shift of resonant fluorescence spectrum(RFS)in a room-temperature two-levelatomic system. In this paper, we present a detail analysis of the physics mechanism of the Doppler shift and propose a method to measure the component of the Dicke states (the atomic polymers with different masses)by using the Doppler shift of the RFS.
Multiphoton absorption (MPA) is a nonlinear optical process that involves simultaneous absorption of two or more photons by a material to promote its ground state to an excited state. Multiphoton absorption promises many important applications such as multi-dimensional fluorescence imaging, three dimensional (3D) data storage. Physical and chemical properties of nanometer sized semiconductor materials change drastically due to quantum size effect. Combination of both multiphoton absorption and quantum effects will be an interesting study. Multiphoton absorption of semiconducting nanomaterials …
Multiphoton microscopy has enabled us to image cellular dynamics in vivo. However, the excitation wavelength for imaging with commercially available lasers is mostly limited between 650-1040 nm. Here we develop a femtosecond fiber laser system that produces $\sim$150 fs pulses at 1.8 $μ$m. Our system starts from an erbium-doped silica fiber laser, and its wavelength is converted to 1.8 $μ$m using a Raman shift fiber. The 1.8 $μ$m pulses are amplified with a two-stage Tm:ZBLAN fiber amplifier. The final pulse energy is $\sim$1 $μ$J, sufficient for in vivo imaging.
Two-Photon Microscopy has become an invaluable tool for biological and medical research, providing high sensitivity, molecular specificity, inherent three-dimensional sub-cellular resolution and deep tissue penetration. In terms of imaging speeds, however, mechanical scanners still limit the acquisition rates to typically 10-100 frames per second. Here we present a high-speed non-linear microscope achieving kilohertz frame rates by employing pulse-modulated, rapidly wavelength-swept lasers and inertia-free beam steering through angular dispersion. In combination with a high bandwidth, single-p…
This work presents a theoretical analysis of the Autler-Townes splitting pattern in the four-wave mixing signal generated in a three-level cascade Doppler-broadened system. We employ the density matrix formalism to write the Bloch equations and solve them numerically. The solutions allow us to compare the response of the upper level population and the generated signal coherence for homogeneously and non-homogeneously broadened systems. Our results reveal an AC Stark shift in the nonlinear signal when the frequency of the strong or weak beam is scanned, in contrast to what is observed in the fl…
In this work, we introduce the platform of plasmonic Doppler grating (PDG) to experimentally investigate the enhancement effect of plasmonic gratings in the input and output beams of nonlinear surface-enhanced coherent anti-Stokes Raman scattering (SECARS). PDGs are designable azimuthally chirped gratings that provide broadband and spatially dispersed plasmonic enhancement. Therefore, they offer the opportunity to observe and compare the overall enhancement from different combinations of enhancement in individual input and output beams. We first confirm PDG's capability of spatially separating…
We present an optical scheme to detect the oscillations of a two-ion string confined in a linear Paul trap. The motion is detected by analyzing the intensity correlations in the fluorescence light emitted by one or two ions in the string. We present measurements performed under continuous Doppler cooling and under pulsed illumination. We foresee several direct applications of this detection method, including motional analysis of multi-ion species or coupled mechanical oscillators, and sensing of mechanical correlations.
The ytterbium atom is widely used in the fields of atomic physics, cavity quantum electrodynamics, quantum information processing and optical frequency standards. There is however a strong dispersion among the reported values of the ${}^1{\rm S}_0 \rightarrow {}^1{\rm P}_1$ transition frequency. In this article, we present two independent measurements of the absolute frequency of this transition performed with two different wavemeters using atomic fluorescence spectroscopy. The cancellation of Doppler shifts is obtained by fine tuning the angle between the probe laser and the atomic beam. The …
