| 1. | S. Rajagopal; T. J. Allen; M. Berendt; D. Lin; S. Alam; D. J. Richardson; B. T. Cox The effect of source backing materials and excitation pulse durations on laser-generated ultrasound waveforms Journal Article In: J. Acoust. Soc. Am., 153 (5), pp. 2649, 2023. Links | BibTeX @article{2023-Rajagopal-JASA,
title = {The effect of source backing materials and excitation pulse durations on laser-generated ultrasound waveforms},
author = {S. Rajagopal and T. J. Allen and M. Berendt and D. Lin and S. Alam and D. J. Richardson and B. T. Cox},
url = {http://bug.medphys.ucl.ac.uk/papers/2023-Rajagopal-JASA.pdf},
doi = {10.1121/10.0019306},
year = {2023},
date = {2023-05-01},
journal = {J. Acoust. Soc. Am.},
volume = {153},
number = {5},
pages = {2649},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
| 2. | M. Bakaric; P. Fromme; A. Hurrell; S. Rajagopal; P. Miloro; B. Zeqiri; B. T. Cox; B. E. Treeby Measurement of the temperature-dependent output of lead zirconate titanate transducers Journal Article In: Ultrasonics, 114 , pp. 106378, 2021. Links | BibTeX @article{2021-Bakaric-ULTRASONICS,
title = {Measurement of the temperature-dependent output of lead zirconate titanate transducers},
author = {M. Bakaric and P. Fromme and A. Hurrell and S. Rajagopal and P. Miloro and B. Zeqiri and B. T. Cox and B. E. Treeby},
url = {http://bug.medphys.ucl.ac.uk/papers/2021-Bakaric-ULTRASONICS.pdf},
doi = {10.1016/j.ultras.2021.106378},
year = {2021},
date = {2021-02-05},
journal = {Ultrasonics},
volume = {114},
pages = {106378},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
| 3. | S. Rajagopal; B. T. Cox Modelling laser ultrasound waveforms: The effect of varying pulse duration and material properties Journal Article In: Journal of the Acoustical Society of America, 149 (3), pp. 2040-2054, 2021. Abstract | Links | BibTeX @article{2021-Rajagopal-JASA,
title = {Modelling laser ultrasound waveforms: The effect of varying pulse duration and material properties},
author = {S. Rajagopal and B. T. Cox},
url = {http://bug.medphys.ucl.ac.uk/papers/2021-Rajagopal-JASA.pdf},
doi = {10.1121/10.0003558},
year = {2021},
date = {2021-01-29},
journal = {Journal of the Acoustical Society of America},
volume = {149},
number = {3},
pages = {2040-2054},
abstract = {Optical generation of ultrasound using nanosecond duration laser pulses has generated great interest both in industrial and biomedical applications. The availability of portable laser devices using semiconductor technology and optical fibres, as well as numerous source material types based on nanocomposites, has proliferated the applications of laser ultrasound. The nanocomposites can be deposited on the tip of optical fibres as well as planar hard and soft backing materials using various fabrication techniques, making devices suitable for a variety of applications. The ability to choose the acoustic material properties and the laser pulse duration gives considerable control over the ultrasound output. Here, an analytical time-domain solution is derived for the acoustic pressure waveform generated by a planar optical ultrasound source consisting of an optically absorbing layer on a backing. It is shown that by varying the optical attenuation coefficient, the thickness of the absorbing layer, the acoustic proper- ties of the materials, and the laser pulse duration, a wide variety of pulse shapes and trains can be generated. It is shown that a source with a reflecting backing can generate pulses with higher amplitude than a source with an acoustically-matched backing in the same circumstances when stress-confinement has not been satisfied.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Optical generation of ultrasound using nanosecond duration laser pulses has generated great interest both in industrial and biomedical applications. The availability of portable laser devices using semiconductor technology and optical fibres, as well as numerous source material types based on nanocomposites, has proliferated the applications of laser ultrasound. The nanocomposites can be deposited on the tip of optical fibres as well as planar hard and soft backing materials using various fabrication techniques, making devices suitable for a variety of applications. The ability to choose the acoustic material properties and the laser pulse duration gives considerable control over the ultrasound output. Here, an analytical time-domain solution is derived for the acoustic pressure waveform generated by a planar optical ultrasound source consisting of an optically absorbing layer on a backing. It is shown that by varying the optical attenuation coefficient, the thickness of the absorbing layer, the acoustic proper- ties of the materials, and the laser pulse duration, a wide variety of pulse shapes and trains can be generated. It is shown that a source with a reflecting backing can generate pulses with higher amplitude than a source with an acoustically-matched backing in the same circumstances when stress-confinement has not been satisfied. |
| 4. | S. Rajagopal; B. T. Cox 100 MHz bandwidth planar laser-generated ultrasound source for hydrophone calibration Journal Article In: Ultrasonics, 108 , pp. 106218, 2020. Links | BibTeX @article{2020-Rajagopal-ULTRASONICS,
title = {100 MHz bandwidth planar laser-generated ultrasound source for hydrophone calibration},
author = {S. Rajagopal and B. T. Cox},
url = {http://bug.medphys.ucl.ac.uk/papers/2020-Rajagopal-ULTRASONICS.pdf},
doi = {10.1016/j.ultras.2020.106218},
year = {2020},
date = {2020-07-12},
journal = {Ultrasonics},
volume = {108},
pages = {106218},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
| 5. | S. Rajagopal; T. Sainsbury; B. E. Treeby; B. T. Cox Laser generated ultrasound sources using carbon-polymer nanocomposites for high frequency metrology Journal Article In: J. Acoust. Soc. Am., 144 (2), pp. 584-597, 2018. Links | BibTeX @article{Rajagopal2018,
title = {Laser generated ultrasound sources using carbon-polymer nanocomposites for high frequency metrology},
author = {S. Rajagopal and T. Sainsbury and B. E. Treeby and B. T. Cox},
url = {http://bug.medphys.ucl.ac.uk/papers/2018-Rajagopal-JASA.pdf},
doi = {10.1121/1.5048413},
year = {2018},
date = {2018-08-03},
journal = {J. Acoust. Soc. Am.},
volume = {144},
number = {2},
pages = {584-597},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
| 6. | T. Koukoulas; S. Robinson; S. Rajagopal; B. Zeqiri A comparison between heterodyne and homodyne interferometry to realise the SI unit of acoustic pressure in water Journal Article In: Metrologia, 53 (2), pp. 891–898, 2016. Links | BibTeX @article{Koukoulas2016,
title = {A comparison between heterodyne and homodyne interferometry to realise the SI unit of acoustic pressure in water},
author = {T. Koukoulas and S. Robinson and S. Rajagopal and B. Zeqiri},
doi = {10.1088/0026-1394/53/2/891},
year = {2016},
date = {2016-03-31},
journal = {Metrologia},
volume = {53},
number = {2},
pages = {891--898},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
| 7. | S. Rajagopal; N. Sadhoo; B. Zeqiri Reference characterisation of sound speed and attenuation of the IEC agar-based tissue-mimicking material up to a frequency of 60 MHz Journal Article In: Ultrasound Med. Biol., 41 (1), pp. 317–333, 2015. Links | BibTeX @article{Koukoulas2016a,
title = {Reference characterisation of sound speed and attenuation of the IEC agar-based tissue-mimicking material up to a frequency of 60 MHz},
author = {S. Rajagopal and N. Sadhoo and B. Zeqiri},
doi = {10.1016/j.ultrasmedbio.2014.04.018},
year = {2015},
date = {2015-01-01},
journal = {Ultrasound Med. Biol.},
volume = {41},
number = {1},
pages = {317--333},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
| 8. | D. A. Kenwright; N. Sadhoo; S. Rajagopal; T. Anderson; C. M. Morgan; P. W. Hadoke; G. A. Gray; B. Zeqiri; P. R. Hoskins Acoustic assessment of a konjac–carrageenan tissue-mimicking material at 5–60 MHz Journal Article In: Ultrasound Med. Biol., 40 (12), pp. 2895–2902, 2014. Links | BibTeX @article{Kenwright2014,
title = {Acoustic assessment of a konjac–carrageenan tissue-mimicking material at 5–60 MHz},
author = {D. A. Kenwright and N. Sadhoo and S. Rajagopal and T. Anderson and C. M. Morgan and P. W. Hadoke and G. A. Gray and B. Zeqiri and P. R. Hoskins},
doi = {10.1016/j.ultrasmedbio.2014.07.006},
year = {2014},
date = {2014-12-01},
journal = {Ultrasound Med. Biol.},
volume = {40},
number = {12},
pages = {2895--2902},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
| 9. | S. Rajagopal; B. Zeqiri; P. N. Gelat Calibration of miniature medical ultrasonic hydrophones for frequencies in the range 100 to 500 kHz using an ultrasonically absorbing waveguide Journal Article In: IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 61 (5), pp. 765–778, 2014. Links | BibTeX @article{Rajagopal2014,
title = {Calibration of miniature medical ultrasonic hydrophones for frequencies in the range 100 to 500 kHz using an ultrasonically absorbing waveguide},
author = {S. Rajagopal and B. Zeqiri and P. N. Gelat},
doi = {10.1109/TUFFC.2014.2969},
year = {2014},
date = {2014-04-30},
journal = {IEEE Trans. Ultrason. Ferroelectr. Freq. Control},
volume = {61},
number = {5},
pages = {765--778},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
| 10. | T. Koukoulas; S. Rajagopal; S. Robinson; B. Moss; B. Zeqiri; P. Theobald Primary ultrasonic interferometer photodiode characterization using frequency-modulated laser wavefront radiation Journal Article In: Metrologia, 50 (6), pp. 572–579, 2013. Links | BibTeX @article{Koukoulas2013,
title = {Primary ultrasonic interferometer photodiode characterization using frequency-modulated laser wavefront radiation},
author = {T. Koukoulas and S. Rajagopal and S. Robinson and B. Moss and B. Zeqiri and P. Theobald},
doi = {10.1088/0026-1394/50/6/572},
year = {2013},
date = {2013-10-15},
journal = {Metrologia},
volume = {50},
number = {6},
pages = {572--579},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
| 11. | B. Zeqiri; G. Zauhar; S. Rajagopal; A. Pounder Systematic evaluation of a secondary method for measuring diagnostic-level medical ultrasound transducer output power based on a large-area pyroelectric sensor Journal Article In: Metrologia, 49 (3), pp. 368–381, 2012. Links | BibTeX @article{Zeqiri2012,
title = {Systematic evaluation of a secondary method for measuring diagnostic-level medical ultrasound transducer output power based on a large-area pyroelectric sensor},
author = {B. Zeqiri and G. Zauhar and S. Rajagopal and A. Pounder},
doi = {10.1088/0026-1394/49/3/368},
year = {2012},
date = {2012-04-24},
journal = {Metrologia},
volume = {49},
number = {3},
pages = {368--381},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
| 12. | S. Rajagopal; A. Shaw The buoyancy method - a potential new primary ultrasound power standard Journal Article In: Metrologia, 49 (3), pp. 327–339, 2012. Links | BibTeX @article{Rajagopal2012,
title = {The buoyancy method - a potential new primary ultrasound power standard},
author = {S. Rajagopal and A. Shaw},
doi = {10.1088/0026-1394/49/3/327},
year = {2012},
date = {2012-04-04},
journal = {Metrologia},
volume = {49},
number = {3},
pages = {327--339},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
| 13. | J. W. Hand; A. Shaw; N. Sadhoo; S. Rajagopal; R. J. Dickinson; L. R. Gavrilov A random phased array device for delivery of high intensity focused ultrasound Journal Article In: Phys. Med. Biol., 54 (19), pp. 5675–5693, 2009. Links | BibTeX @article{Hand2009,
title = {A random phased array device for delivery of high intensity focused ultrasound},
author = {J. W. Hand and A. Shaw and N. Sadhoo and S. Rajagopal and R. J. Dickinson and L. R. Gavrilov},
doi = {10.1088/0031-9155/54/19/002},
year = {2009},
date = {2009-09-01},
journal = {Phys. Med. Biol.},
volume = {54},
number = {19},
pages = {5675--5693},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
