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35 results on '"Dasa, Manoj. K."'

1. Multi-wavelength high energy gas-filled fiber Raman laser spanning from 1.53 um to 2.4 um

Author

Adamu, Abubakar I., Wang, Yazhou, Habib, MD. Selim, Dasa, Manoj. K., Antonio-Lopez, J. E, Amezcua-Correa, Rodrigo, Bang, Ole, and Markos, Christos

Subjects
Physics - Optics
Abstract

In this work, we present a high pulse energy multi-wavelength Raman laser spanning from 1.53 um up to 2.4 um by employing the cascaded rotational stimulated Raman scattering (SRS) effect in a 5-m hydrogen (H2) -filled nested anti-resonant fiber (NARF), pumped by a linearly polarized Er/Yb fiber laser with a peak power of ~13 kW and pulse duration of ~7 ns in the C-band. The developed Raman laser has distinct lines at 1683 nm, 1868 nm, 2100 nm, and 2400 nm, with pulse energies as high as 18.25 uJ, 14.4 uJ, 14.1 uJ, and 8.2 uJ, respectively. We demonstrate how the energy in the Raman lines can be controlled by tuning the H2 pressure from 1 bar to 20 bar

Published
2020
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8. Enhancing the axial resolution of an optoacoustic microscopy imaging instrument by using a pico-second pulse duration laser

Author

Kim, Chulhong, Laufer, Jan, Ntziachristos, Vasilis, Zemp, Roger J., Nteroli, Gianni, Messa, Giulia, Koutsikou, Stella, Dasa, Manoj K., Penttinen, Antti, Härkönen, Antti, Guina, Mircea, Podoleanu, Adrian, Bradu, Adrian, Kim, Chulhong, Laufer, Jan, Ntziachristos, Vasilis, Zemp, Roger J., Nteroli, Gianni, Messa, Giulia, Koutsikou, Stella, Dasa, Manoj K., Penttinen, Antti, Härkönen, Antti, Guina, Mircea, Podoleanu, Adrian, and Bradu, Adrian

Abstract

In conventional optoacoustic microscopy, nanosecond pulse duration lasers are employed. When a laser delivering shorter pulse durations is used, it is expected that, from a theoretical point of view, broader, higher-frequency acoustic waves to be generated, therefore a better axial resolution of the instrument. In the present report, this advantage, offered by a picosecond duration pulse laser, to experimentally demonstrate that the axial resolution of an optoacoustic microscopy instrument can be enhanced was exploited. In comparison to a 2 ns pulse duration, an improvement in the axial resolution of ~50% is demonstrated by using excitations with pulses of duration <100 ps. Details of an optoacoustic microscopy instrument, operating at 532 nm, capable to provide high-resolution axial and lateral optoacoustic images, are also presented. The capabilities of the instrument are demonstrated by in-vivo images of Xenopus laevis brain with a similar ~ 3.8 µm lateral resolution throughout the whole axial imaging range.

Published
2023

9. Photoacoustic detection of CO2 using a H2-filled mid-infrared fiber Raman laser source

Author

Wang, Yazhou, Dasa, Manoj K., Antonio-Lopez, J. E., Correa, Rodrigo Amezcua, Markos, Christos, Oraevsky, Alexander A., and Wang, Lihong V.

Subjects
Photoacoustic detection, Gas-filled fiber Raman laser, Mid-infrared laser, CO2 detection
Abstract

Unraveling the scientific and technological importance of the mid-infrared (mid-IR) region remains yet a long-standing challenge. Despite the significant efforts on mid-IR light sources, development of high-energy, narrow-linewidth and compact lasers still constitutes the main obstacle towards novel spectroscopic, imaging and sensing devices. Photoacoustic modality is known as one of the most powerful tools enabling high signal-to-noise ratio gas detection and albeit its wide use in the mature near-infrared (near-IR) region, further research has to be carried out in the mid-IR in order to “unlock” its full potential. In this work, we aim on tracing CO2 based on the innovative combination of the emerging gas-filled mid-IR silica anti-resonant hollow-core fiber (ARHCF) Raman laser technology with the powerful photoacoustic modality. The laser source adopts the stimulated Raman scattering effect of H2 filled in a piece of ARHCF, to enable the generation of first-order vibrational Raman Stokes from a 1533 nm Er-doped fiber laser pump. With this configuration, a nanosecond laser pulses with micro-joule level pulse energy is achieved at ~ 4.25 μm wavelength, which is located within the strongest absorption band of CO2. The laser’s linewidth is estimated to be tens GHz level. This laser source is used to drive an in-house developed photoacoustic sensor, revealing a 1.78 ppm level CO2 detection limit in laboratory condition. This work provides a valuable reference for the development of high-sensitivity gas detectors.

Published
2023

15. Ultraviolet to mid-infrared gas-filled anti-resonant hollow-core fiber lasers

Author

Wang, Yazhou, primary, Adamu, Abubakar I., additional, Habib, Md. Selim, additional, Dasa, Manoj K., additional, Petersen, Christian R., additional, Antonio-Lopez, J. Enrique, additional, Zhou, Binbin, additional, Jepsen, Peter Uhd ., additional, Schülzgen, Axel, additional, Bache, Morten, additional, Amezcua Correa, Rodrigo, additional, Bang, Ole, additional, and Markos, Christos, additional

Published
2021
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23. Long Wavelength Mid-Infrared Supercontinuum Source

Author

Woyessa, Getinet, primary, Dasa, Manoj K., additional, Kwarkye, Kyei, additional, Petersen, Christian R., additional, Sidharthan, Raghuraman, additional, Chen, Shaoxiang, additional, Yoo, Seongwoo, additional, and Bang, Ole, additional

Published
2020
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29. Power stable 1.5–10.5??µm cascaded mid-infrared supercontinuum laser without thulium amplifier

Author

Woyessa, Getinet, Kwarkye, Kyei, Dasa, Manoj K., Petersen, Christian R., Sidharthan, Raghuraman, Chen, Shaoxiang, Yoo, Seongwoo, and Bang, Ole

Abstract

We demonstrate a simple and power stable 1.5–10.5 µm cascaded mid-infrared 3 MHz supercontinuum fiber laser. To increase simplicity and decrease cost, the design of the fiber cascade is optimized so that no thulium amplifier is needed. Despite the simple design with no thulium amplifier, we demonstrate a high average output power of 86.6 mW. Stability measurements for seven days with 8–9 h operation daily revealed fluctuations in the average power with a standard deviation of only 0.43% and a power spectral density stability of ±0.18dBm/nm for wavelengths <10µm. The high-repetition-rate, robust, and cheap all-fiber design makes this source ideal for applications in spectroscopy and imaging.

Published
2021

30. Multi-wavelength high-energy gas-filled fiber Raman laser spanning from 1.53??µm to 2.4??µm

Author

Adamu, Abubakar I., Wang, Yazhou, Habib, Md. Selim, Dasa, Manoj. K., Antonio-Lopez, J. E., Amezcua-Correa, Rodrigo, Bang, Ole, and Markos, Christos

Abstract

In this work, we present a high-pulse-energy multi-wavelength Raman laser spanning from 1.53 µm up to 2.4 µm by employing the cascaded rotational stimulated Raman scattering effect in a 5 m hydrogen (H_2)-filled nested anti-resonant fiber, pumped by a linearly polarized Er/Yb fiber laser with a peak power of ∼13kW and pulse duration of ∼7ns in the C-band. The developed Raman laser has distinct lines at 1683 nm, 1868 nm, 2100 nm, and 2400 nm, with pulse energies as high as 18.25 µJ, 14.4 µJ, 14.1 µJ, and 8.2 µJ, respectively. We demonstrate how the energy in the Raman lines can be controlled by tuning the H_2 pressure from 1 bar to 20 bar.

Published
2021

35. High pulse energy and quantum efficiency mid-infrared gas Raman fiber laser targeting CO 2 absorption at 4.2  µm.

Author

Wang Y, Dasa MK, Adamu AI, Antonio-Lopez JE, Habib MS, Amezcua-Correa R, Bang O, and Markos C

Abstract

In this Letter, we demonstrate a high pulse energy and linearly polarized mid-infrared Raman fiber laser targeting the strongest absorption line of ${\rm CO}&#95;2$CO 2 at $\sim{4.2}\;\unicode {x00B5} {\rm m}$∼4.2µm. This laser was generated from a hydrogen (${\rm H}&#95;2$H 2 )-filled antiresonant hollow-core fiber, pumped by a custom-made 1532.8 nm Er-doped fiber laser delivering 6.9 ns pulses and 11.6 kW peak power. A quantum efficiency as high as 74% was achieved, to yield 17.6 µJ pulse energy at 4.22 µm. Less than 20 bar ${\rm H}&#95;2$H 2 pressure was required to maximize the pulse energy since the transient Raman regime was efficiently suppressed by the long pump pulses.

Published
2020
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