Sub-100 ps Monolithic Diamond Raman Laser Emitting at 573 nm

Energy scaling of the 1st Stokes oscillation is compared in micro-lensed and plane-plane monolithic diamond Raman lasers under 532 nm pumping. A maximum Raman pulse energy of 92 µJ at 573 nm was achieved with the micro-lensed device, while in a plane-plane configuration the maximum Raman pulse energy was 3.1 mJ. 2nd Stokes generation at 620 nm in 2 and 1 mm long micro-lensed monolithic diamond Raman lasers is also reported. The best conversion efficiency from the pump at 532 nm, namely 63 %, was observed in a 2 mm long crystal at the pump pulse intensity of 4.5 GW/cm 2. By measuring the output Raman laser beam caustic it was found that the 2nd Stokes intracavity beam radius at the output coupler of the micro-lensed device is at least two times smaller than that expected from the ABCD matrix calculations of the resonator mode. A Raman gain-guiding mechanism is suggested to explain this difference.

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“…The highest pulse energy reported so far from a DRL operating in the visible spectral range [16][17][18]20] is 0.3 mJ [20].…”

Section: A 1 St Stokes Emission Energy Scalingmentioning

confidence: 98%

Energy Scaling, Second Stokes Oscillation, and Raman Gain-Guiding in Monolithic Diamond Raman Lasers

Savitski

Demetriou

Reilly

et al. 2018

IEEE J. Quantum Electron.

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“…The first Stokes emission line from the diamond at 573 nm is used as the excitation light source to illuminate the sample in spectrometer. The laser exhibits a maximum average output power of 175 mW with a pulse width of 71 ps at 573 nm [37]. When used in the spectrometer, the current to the pump laser was adjusted so that the average output power at 573 nm was approximately 25 mW.…”

Section: Structure Of the Spectrometermentioning

confidence: 99%

“…At 25 mW power level, the measured pulse width was in a range of 70-100 ps (FWHM) and the pulse rate was 70 kHz. A detailed description of the laser can be found in [37].…”

Section: Structure Of the Spectrometermentioning

confidence: 99%

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Time-Resolved Raman Spectrometer With High Fluorescence Rejection Based on a CMOS SPAD Line Sensor and a 573-nm Pulsed Laser

Talala

Kaikkonen

Keränen

et al. 2021

IEEE Trans. Instrum. Meas.

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A time-resolved Raman spectrometer is demonstrated based on a 256×8 CMOS SPAD line sensor and a 573 nm fiber-coupled diamond Raman laser delivering pulses with duration below 100 ps FWHM. The collected back scattered light from the sample is dispersed on the line sensor using a custom volume holographic grating having 1800 lines/mm. Efficient fluorescence rejection in the Raman measurements is achieved due to a combination of time gating on sub-100 ps-time scale and a 573 nm excitation wavelength. To demonstrate the performance of the spectrometer, fluorescent oil samples were measured. For organic sesame seed oil having a continuous wave mode fluorescence-to-Raman ratio of 10.5 and a fluorescence lifetime of 2.7 ns, a signal-to-distortion value of 76.2 was achieved. For roasted sesame seed oil having a continuous wave mode fluorescence-to-Raman ratio of 82 and a fluorescence lifetime of 2.2 ns, a signal-to-distortion value of 28.2 was achieved. In both cases, the fluorescence-to-Raman ratio was reduced by a factor of 24-25 owing to time gating. For organic oil, spectral distortion was dominated by dark counts while for the more fluorescent roasted oil, the main source of spectral distortion was timing skew of the sensor. With the presented post-processing techniques, the level of distortion could be reduced by 88-89 % for both samples. Compared to common 532 nm excitation, approximately 73 % lower fluorescence-to-Raman ratio was observed for 573 nm excitation when analyzing the organic sesame seed oil. Index Terms-Fluorescence rejection, Raman laser, Raman spectrometer, Raman spectroscopy, SPAD sensor, time-correlated single photon counting, time gating, timing skew I. INTRODUCTION AMAN spectroscopy is used in a wide range of fields including food and oil industries, mining industry, medical diagnostics, pharmacy, forensic science and archaeometry [1]

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“…The broad visible wavelength absorption, which is the focus in the present study, allows for multiple laser wavelengths in the visible range and improves robustness of the sensing concept against wavelength fluctuations relative to the narrow absorption of the infrared transition. Laser operation is also compatible across a wide range of temporal regimes (continuous to ultrafast pulses) [37,38,39,40,41]. Designs have been demonstrated in several physical formats including high-power free-space designs [35], efficient monolithic devices [42] and miniature on-chip devices with low threshold (< 80 mW [43]).…”

Section: Introductionmentioning

confidence: 99%

Absorptive laser threshold magnetometry: combining visible diamond Raman lasers and nitrogen-vacancy centres

Nair

Rogers

Spence

et al. 2021

Mater. Quantum. Technol.

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We propose a high-sensitivity magnetometry scheme based on a diamond Raman laser with visible pump absorption by an ensemble of coherently microwave driven negatively charged nitrogen-vacancy centres (NV−) in the same diamond crystal. The NV− centres’ absorption and emission are spin-dependent. We show how the varying absorption of the NV− centres changes the Raman laser output. A shift in the diamond Raman laser threshold and output occurs with the external magnetic field and microwave driving. We develop a theoretical framework with steady-state solutions to describe the effects of coherently driven NV− centres including the charge state switching between NV− and its neutral charge state NV0 in a diamond Raman laser. We discuss that such a laser working at the threshold can be employed for magnetic field sensing. In contrast to previous studies on NV− magnetometry with visible laser absorption, the laser threshold magnetometry method is expected to have low technical noise, due to low background light in the measurement signal. For magnetic-field sensing, we project a shot-noise limited DC sensitivity of a few pT / H z in a well-calibrated cavity with realistic parameters. This sensor employs the broad visible absorption of NV− centres and unlike previous laser threshold magnetometry proposals it does not rely on active NV− centre lasing or an infrared laser medium at the specific wavelength of the NV− centre’s infrared absorption line.

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Sub-100 ps Monolithic Diamond Raman Laser Emitting at 573 nm

Cited by 6 publications

References 21 publications

Energy Scaling, Second Stokes Oscillation, and Raman Gain-Guiding in Monolithic Diamond Raman Lasers

Energy Scaling, Second Stokes Oscillation, and Raman Gain-Guiding in Monolithic Diamond Raman Lasers

Time-Resolved Raman Spectrometer With High Fluorescence Rejection Based on a CMOS SPAD Line Sensor and a 573-nm Pulsed Laser

Absorptive laser threshold magnetometry: combining visible diamond Raman lasers and nitrogen-vacancy centres

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