A type of beat in nonlinear optical spectroscopy that is distinct from quantum beats (QB's) and polarization beats, is described. Like a quantum beat, this beat, which we refer to as an accidental degeneracy beat (ADB), can only be seen in multilevel systems. However, unlike quantum beats, which are the result of intramolecular interferences, ADB's are interferences between different subensembles of molecules in the sample. They require multilevel systems with spectral overlap. ADB's can appear as separate frequencies or as phase and amplitude contributions with the same frequency as that of quantum beats. A procedure for distinguishing between quantum beats and ADB's is outlined, and criteria under which ADB's are expected to be observed are delineated. Calculations of the spectrally resolved stimulated vibrational echo signal from an inhomogeneously broadened coupled anharmonic oscillator system are presented to illustrate the differences between the two types of beats. ADB's carry information about the anharmonicity of a system, while QB's carry information about intramolecular correspondence of transition frequencies in a multilevel system.A type of beat in nonlinear optical spectroscopy that is distinct from quantum beats (QB's) and polarization beats, is described. Like a quantum beat, this beat, which we refer to as an accidental degeneracy beat (ADB), can only be seen in multilevel systems. However, unlike quantum beats, which are the result of intramolecular interferences, ADB's are interferences between different subensembles of molecules in the sample. They require multilevel systems with spectral overlap. ADB's can appear as separate frequencies or as phase and amplitude contributions with the same frequency as that of quantum beats. A procedure for distinguishing between quantum beats and ADB's is outlined, and criteria under which ADB's are expected to be observed are delineated. Calculations of the spectrally resolved stimulated vibrational echo signal from an inhomogeneously broadened coupled anharmonic oscillator system are presented to illustrate the differences between the two types of beats. ADB's carry information about the anharmonicity of a system, while QB's carry information about intramolecular correspondence of transition frequencies in a multilevel system.

Physical Review AJan 17, 200222 citations

Optical-domain spectral super-resolution enabled by a quantum memory

Mateusz Mazelanik, Adam Leszczyński, Michal P. Parniak

Existing super-resolution methods of optical imaging hold a solid place as an application in multiple sciences, but many new developments allow beating of diffraction limit in better and more subtle ways. An avenue was opened by suggesting to fully exploit information already present in the field by performing quantum-inspired tailored measurements. Here we exploit the full spectral information of the optical field in order to beat the Rayleigh limit in spectroscopy. We employ optical quantum memory with spin-wave storage and an embedded processing capability to implement a timeinversion interferometer for input light, projecting the optical field in the symmetricanti-symmetric mode basis. Our tailored measurement achieves a resolution of 15 kHz and requires 20.1 times less photons than a corresponding Rayleigh-limited conventional method. We demonstrate the advantage of our technique over both conventional spectroscopy and heterodyne measurements, showing potential for application in distinguishing ultra-narrowband emitters, optical communication channels, or signals transduced from lower-frequency domains.Existing super-resolution methods of optical imaging hold a solid place as an application in multiple sciences, but many new developments allow beating of diffraction limit in better and more subtle ways. An avenue was opened by suggesting to fully exploit information already present in the field by performing quantum-inspired tailored measurements. Here we exploit the full spectral information of the optical field in order to beat the Rayleigh limit in spectroscopy. We employ optical quantum memory with spin-wave storage and an embedded processing capability to implement a timeinversion interferometer for input light, projecting the optical field in the symmetricanti-symmetric mode basis. Our tailored measurement achieves a resolution of 15 kHz and requires 20.1 times less photons than a corresponding Rayleigh-limited conventional method. We demonstrate the advantage of our technique over both conventional spectroscopy and heterodyne measurements, showing potential for application in distinguishing ultra-narrowband emitters, optical communication channels, or signals transduced from lower-frequency domains.

Jun 8, 20210 citations

Laser Spectroscopy and Quantum Optics

Theodor W. Hänsch, HERBERT WALTHER

Springer eBooksJan 1, 19991 citation

Quantum-Limit Spectroscopy

Z. Ficek, R. Tanaś

Springer series in optical sciences/SPringer series in optical sciencesNov 7, 201616 citations

Observation of Quantum Beats in Photon Echoes and Optical Nutation

R. L. Shoemaker, Frederic A. Hopf

We extend the technique of quantum-beat spectroscopy to the infrared region by utilizing the strong, directional absorption and emission which occurs in photon echoes and optical nutation. Using a vibrational transition of N ${\mathrm{H}}_{2}$ D, we have made the first observations of infrared quantum beats in these phenomena. The hyperfine splitting which produces the quantum beats has not been observed in Lamb-dip spectroscopy but is clearly resolved in these time domain studies.We extend the technique of quantum-beat spectroscopy to the infrared region by utilizing the strong, directional absorption and emission which occurs in photon echoes and optical nutation. Using a vibrational transition of N${\mathrm{H}}_{2}$D, we have made the first observations of infrared quantum beats in these phenomena. The hyperfine splitting which produces the quantum beats has not been observed in Lamb-dip spectroscopy but is clearly resolved in these time domain studies.

Physical Review LettersDec 23, 197453 citations

{\mathrm{H}}_{2}

D, we have made the first observations of infrared quantum beats in these phenomena. The hyperfine splitting which produces the quantum beats has not been observed in Lamb-dip spectroscopy but is clearly resolved in these time domain studies.