A New Phase-Coherent Light Scattering Method: First Observation of Complex Brillouin Spectra

Tanaka, Hajime; Sonehara, Tsuyoshi; Takagi, Sadayuki F.

doi:10.1103/physrevlett.79.881

Cited by 32 publications

(19 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The detailed description and procedures of the COBS method for the ultrasonic velocity measurement have been given in the literature, 8 however, only a brief outline is given here. We used two frequency-tunable lasers with a power of 200 mW (Model 140-0532-200, Lightwave Electronics; single axial mode, continuous wave output, frequency-doubled green Nd:YAG laser) in our COBS apparatus.…”

Section: Ultrasonic Velocity and Density Measurementsmentioning

confidence: 99%

“…Recently, a new phase-coherent light-scattering method, the coherent Brillouin scattering (COBS), was developed by Tanaka et al 8 This method is a light-scattering technique in which the light is scattered by optically generated coherent phonons instead of thermally excited phonons. In this method, the scattered light is detected as a heterodyne signal in the lock-in detection.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Acoustic characteristics of PMMA in the steady stress-strain state investigated by coherent Brillouin scattering method

Sakurai

Matsuoka

Koda

et al. 2000

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

ABSTRACT:The acoustic properties of PMMA poly(methyl methacrylate) deformed by tensile stress were investigated by the coherent Brillouin scattering method. The ultrasonic velocities of PMMA in steady stress-strain states were measured in the frequency range of 100 MHz to 1 GHz. The ultrasonic velocities decreased with increasing strain, and the ratio of the decrease increased with increasing strain rate. This result indicates that the crazing residues still remain in the steady stress-strain states, and the amount of the residues depends upon the strain rate. The velocity dispersion was observed around 400 MHz for virgin and deformed PMMA and reproduced with a single relaxation process. The relaxation process is assigned to the ␥-relaxation according to the dispersion map for methyl group relaxation in PMMA. The relaxation frequency and strength were independent of the applied stress and strain. The viscoelastic and plastic deformations have little effect on the ␥-relaxation.

show abstract

Section: Ultrasonic Velocity and Density Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Acoustic characteristics of PMMA in the steady stress-strain state investigated by coherent Brillouin scattering method

Sakurai

Matsuoka

Koda

et al. 2000

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

show abstract

“…Finally, if the phase velocity of the optical grating coincides with the phonon velocity, acoustic phonon can resonantly be excited via the electrostriction effects [10,11]. The Brillouin shift frequency satisfies the dispersion relation !…”

mentioning

confidence: 99%

“…Thus, our method for Rayleigh scattering (phase-coherent Rayleigh scattering, CORS) can selectively excite the thermal diffusion mode as largely as possible by increasing the amplitude of the optically generated temperature grating. Moreover, COLS has another advantage over conventional methods including FRS: we can detect only the scattering from the light-induced coherent mode while completely rejecting that from thermally induced incoherent fluctuations, with phase-sensitive optical superheterodyne detection [10,12]. This enables us to observe the thermal diffusion mode even under the influence of large incoherent fluctuations of the orientational relaxation mode without their interference.…”

mentioning

confidence: 99%

Mode-Selective Dynamic Light Scattering Spectroscopy: Application to the Isotropic Phase of Liquid Crystals

Takagi

Tanaka

2004

Phys. Rev. Lett.

Self Cite

View full text Add to dashboard Cite

We have developed a new method of "mode-selective" dynamic light scattering spectroscopy. This method allows us to study dynamic modes usually hidden behind large fluctuations of a critical mode. Here we apply this method to measurements of three dynamic modes of the isotropic phase of liquid crystals near the isotropic-nematic transition. In conventional methods detecting thermally excited modes, the thermal diffusion and sound modes are usually overwhelmed by the orientational relaxation mode since the intensity of the last mode diverges toward the isotropic-nematic critical point. Thanks to the phase-coherent detection ability of our method, we have successfully observed the thermal diffusion and sound modes without the interference of incoherent critical orientational fluctuations.

show abstract

“…We demonstrate here a new method of Rayleigh-Brillouin scattering spectroscopy with a generation of collective dynamics in liquid by two frequency tunable cw laser beams [4], which has both higher resolution and higher S/N ratio, and furthermore no high-frequency limit. We call this "Phase-Coherent Rayleigh-Brillouin scattering" method.…”

Section: Introductionmentioning

confidence: 99%

High resolution phase-coherent Rayleigh-Brillouin scattering method

Takagi¹,

Tanaka²

1998 IEEE Ultrasonics Symposium. Proceedings (Cat. No. 98CH36102)

View full text Add to dashboard Cite

We have developed a new method of Rayleigh-Brillouin spectroscopy, which we call "Phase-Coherent Rayleigh-Brillouin Scattering" method. In our method, we optically generate acoustic phonon by crossing two frequencytunable cw laser beams in a sample. Since the phase of the phonon is coherent to those of the light waves, we can observe complex RayleighBrillouin spectra that cannot be obtained by any methods measuring spontaneous fluctuations. We succeeded in observing the complex Brillouin spectra of carbon disulfide with the phonon frequency at 7.6GHz. This is the highest phonon frequency measured by optical-beating technique using cw lasers, to our knowledge. We applied our method to the study of Rayleigh spectra of thermal diffusion mode in a critical solution of methanol and cyclohexane, and succeeded in measuring the complex Rayleigh spectra of thermal diffusion mode selectively. Even under the strong concentration fluctuations near a critical point, our method enables us by generating phase-coherent temperature gradient to observe Rayleigh spectra of thermal diffusion mode selectively.

show abstract

A New Phase-Coherent Light Scattering Method: First Observation of Complex Brillouin Spectra

Cited by 32 publications

References 12 publications

Acoustic characteristics of PMMA in the steady stress-strain state investigated by coherent Brillouin scattering method

Acoustic characteristics of PMMA in the steady stress-strain state investigated by coherent Brillouin scattering method

Mode-Selective Dynamic Light Scattering Spectroscopy: Application to the Isotropic Phase of Liquid Crystals

High resolution phase-coherent Rayleigh-Brillouin scattering method

Contact Info

Product

Resources

About