Photograph of single frequency green laser operating with 204mW output power

• Single frequency green laser with more than 700 mW output at 532 nm, with M² ~1.03, line width of 12.3MHz and 26% O/O power conversion efficiency using 4W laser diode as the pump source.
• Single frequency UV laser with more than 12mW output at 266 nm, using resonant cavity doubling employing beta BBO as the SHG crystal and 700mW single frequency green laser as the pump source.
• Piezo-electrically tunable single frequency Nd:YVO₄ laser at 1064 nm with –0.47 GHz/V tuning rate and 2.54 GHz tuning range
• Compact, Polarized and nearly diffraction limited laser with 9W output at 1064nm using Nd:YVO₄ crystal with low doping concentration (ie 0.5-at-%)
• Power supply for Laser Diode with TEC based temperature control and automatic 1W and 4W laser diode detection.
• Development of servo control electronics for frequency locking of laser beam to a slave ring cavity with ~1 hour locking period and  <2% power stability.

Studies on Single Frequency Laser

1. SLM performance with axial mode separation in end pumped solid state lasers with short absorption depth
2. S parameter to specify the stability of laser resonators and it relation to misalignment tolerance
3. SLM performance with axial mode separation in end pumped solid state lasers using multimode laser as the pump source
4. Correction factor for multimode beam, when it undergoes spherical aberration effect while passing trough a simple lens

The list of publications

A. In Journal: 19 Nos.

 YEAR 2013

1. “Photorefractive properties of Fe, Zn co-doped near stoichiometric LiNbO3  crystals at moderate intensities (0.5 to 6 W/cm2)”,
   R. Bhatt, S. Ganesamoorthy, Indranil Bhaumik, A. Sexana, A.K Karnal and P.K Gupta, Jogy George and K. Ranganathan,
   Opt Las Technol 50, 112-117   (2013)

 YEAR---2010

1. “Effect of pump spectra and axial mode separation on the single longitudinal mode performance in end pumped solid-state lasers with semi-monolithic gain medium”,
   J. George, S. M. Oak, B. P. Singh,
   Opt. Las. Technol. 42, 192 (2010)

 YEAR---2009

1. “Experimental analysis of the effects of orientation and location of the Pockels cell in an Nd:YAG laser resonator”,
   R. Sundar,  K. Ranganathan, J. George and S. M. Oak,
   Opt. Las. Technol.  41, 705 (2009)
   
   
2. “Beam quality degradation of a higher order transverse mode beam due to spherical aberration of a lens”,
   J. George, R. Seihgal, S. M. Oak, S. C. Mehendale,
   Applied optics 48, 6202 (2009).

 YEAR---2007

1. “A study of the effect of axial mode spacing on the single longitudinal mode performance in end pumped solid-state lasers”,
   J. George, J. P.  Xavier, S. C. Mehendale, B. P. Singh, T. P. S. Nathan,
   Opt. Las. Technol.  39, 1193 (2007)
   
   
2. “An alternative method to specify the degree of resonator stability”,
   J. George, K. Ranganathan and T. P. S. Nathan, 
   Pramana J Phy. 68, 571 (2007)

 YEAR---2004

1. “Analysis of laser diode end pumped intracavity frequency doubled, passively Q-switched and mode locked Nd:YVO4 laser”,
   P. K. Mukhopadhyay, M. B Alsous, K. Ranganathan, S. K. Sharma, P. K. Gupta, J. George, T. P. SNathan
   Applied Physics B 79, 713 (2004)

 YEAR---2003

1. “Experimental determination of the thermo-optic coefficient (dn/dT ) and the effective stimulated emission cross-section (σe) of an a-axis cut doped Nd:GdVO4 crystal at 1.06 μm wavelength”,
   P. K. Mukhopadhyay, A. Nautiyal, P. K. Gupta, K. Ranganathan, J. George, S. K. Sharma, T. P. S. Nathan,
   Applied Physics B 77,  81 (2003)
   
   
2. “Simultaneous Q-switching and mode-locking in an intrcavity frequency doubled diode-pumped Nd:YVO4/KTP green laser with Cr:4+YAG”,
   P. K. Mukhopadhyay, M. B. Alsous, K. Ranganathan, P. K. Gupta, J. George, S. K. Sharma, T. P. S. Nathan,
   Optics Communications 222, 399 (2003)
   
   
3. “1.6 W of TEM00 cw output at 1.06 μm from Nd: CNGG laser end-pumped by a fiber-coupled diode laser array”,
   P. K. Mukhopadhyay, K. Ranganathan, J. George, S. K. Sharma, T. P. S. Nathan,
   Opt. Las. Technol.  35, 173 (2003)

YEAR---2002

1. "An alternative approach to determine the fractional heat load in solid state laser materials: application to diode pumped Nd:YVO4 laser",
   P. K. Mukhopadhyay, J. George, K. Ranganathan, S. K. Sharma and T. P. S. Nathan,
   Opt. Las. Technol. 34, 253 (2002).
   
   
2. "Experimental determination of effective stimulated emission cross-section in a diode pumped Nd:YVO4 micro-laser at 1064 nm with various doping concentrations",
   P. K. Mukhopadhyay, J. George, S. K. Sharma, K. Ranganathan and T. P. S. Nathan,
   Opt. Las. Technol. 34, 357 (2002).
   
   
3. "Operational characteristics of dual gain single cavity Nd:YVO4 laser",
   P. K. Mukhopadhyay, J. George, S. K. Sharma, P. K. Gupta and T. P. S. Nathan,
   Pramana J. Phy. 58, 59 (2002).
   
   
4. "Effect of absorbed pump power on quality of output beam from monolithic microchip lasers",
   P. K. Mukhopadhyay, K. Ranganathan, J. George, S. K. Sharma, and T. P. S. Nathan, 
   Pramana J. Phy. 58, p. 657 (2002).
   
   
5. "Effect of Nd3+ concentration on cw and pulsed performance of fiber -coupled diode laser pumped Nd:YVO4 laser at 1064 nm",
   P. K. Mukhopadhyay, K. Ranganathan, J. George, S. K. Sharma, and T. P. S. Nathan,
   Pramana J. Phy. 59 , 75 (2002).

 YEAR---2001

1. “Measurement of st product of solid state laser materials by an alternative method”,
   P. K. Mukhopadhyay, J. George, S. K. Sharma,R. Kapoor and T. P. S. Nathan,
   Pramana J. Phy. 56 , 77  (2001).

YEAR---1999

1. "A new approach to compute Overlap efficiency in axially pumped Sold State Lasers",
   R. Kapoor, P. K. Mukhopadhayay and J. George,
   Opt. Exp.  5, 125 (1999).
   
   
2. “An Alternative approach to determine the spot size of a multi-mode laser beam and its applications to diode laser beams”,
   R. Kapoor, P. K. Mukhopadhyay, J. George, S. K. Sharma,
   Pramana J. Phy., 53, p 307 (1999).
   
   
3. “Thermal Lens measurement techniques in end-pumped solid state lasers; Application to diode pumped microchip lasers”;
   R. Kapoor, P. K. Mukhopadhyay, J. George, S. K. Sharma,
   Pramana J. Phy. 52, 623 (1999).

B.1.  International  Conferences: 05 Nos

 Year-2006

1.  “Highly Efficient Diode Pumped Single Longitudinal Mode Green Laser at 532nm”,
   J. George and  A. K. Nath,
   Photonics 2006, NLO39 (2006)

1. “Effect of axial mode spacing on the SLM performance in end pumped solid-state lasers”,
   J. George, P. K . Mukhopadhyay, V. K. Agnihotri  and T. P. S. Nathan,
   ICOL-2005:31st  International conference on optics and optoelectronis, Dehradun, PP-LA-17 (2005)

 Year-2004

1. “A study of oscillating axial modes in a diode end pumped solid state laser ”, 
   J. George, V. K. Agnihotri, K. Ranganathan, P. K. Mukhopadhyay and T. P. S. Nathan,
   PHOTONICS-2004:Seventh International conference on optoelectronis, fiber optics and photonics , OMD 5.5, p 33 (2004)
   
   
2. “A study of KTP temperature on efficient SLM generation in diode pumped intracavity frequency doubled Nd:YVO4/KTP green laser”,
   J. George, V. K. Agnihotri, K. Ranganathan, P. K. Mukhopadhyay and T. P. S. Nathan,
   PHOTONICS-2004:Seventh International conference on optoelectronis, fiber optics and photonics , NLO P33, p 304 (2004)
   
   
3. “Highly efficient green beam generation by simultaneous side and end pumping of an intracavity doubled Q-switched Nd:YAG laser”,
   P. K. Mukhopadhyay, K. Ranganathan , S. K. Sharma, J. George, R. Sunder, T. P. S. Nathan,
   PHOTONICS-2004:Seventh International conference on optoelectronis, fiber optics and photonics,  9 (2004)

B.2. National  Conferences: 44 Nos

YEAR 2013

1. “Demonstration of nearly Fourier Transform Limited Cr:F laser using Transverse Mode induced Mode Locking”,
   J. George, T. Priyanka, K.S. Bindra  and S. M. Oak,
   DAE BRNS National Laser Symposium NLS-21, MSID 4124 (2013)
   
   
2. “LOPUT Laser: A novel concept to realize single longitudinal mode laser”,
   J. George, K.S. Bindra  and S. M. Oak,
   DAE BRNS National Laser Symposium NLS-21, MSID 4125 (2013)

 YEAR---2012

1. “Demonstration CW Cr:F laser with more than 400 mW output power at 1276 nm using X-folded cavity configuration”,
   J. George, P. K. Mukhopadhyay, K. S. Bindra and S. M. Oak,
   DAE-BRNS National Laser Symposium, 151 (2012).
   
   
2.  “Demonstration of more than 160 mW of gain switched 1240 nm Laser in linear cavity configuration using 8 mm long Cr: Forsterite crystal”,
   J. George, S. K. Sharma, K. Ranganathan, B. N. Upadhyaya, K. S.  Bindra,  S. M. Oak,
   DAE-BRNS National Laser Symposium, 155 (2012).
   
   
3. “Mode-locked Yb-doped fiber oscillator in all-normal-dispersion regime with long gain element: studies on Spectral and temporal profiles”, 
   P. K. Mukhopadhyay, S. K. Sharma, P. K. Gupta, B. N. Upadhyay, U. Chakravarty, A. J. Singh, J.  George, K. S. Bindra, S. M. Oak SM,
   DAE-BRNS National Laser Symposium, 61 (2012).

 YEAR---2010

1. “Photorefractive studies on near-stoichiometric Zn co-doped Fe:LiNbO3 single crystals”,
   R. Bhatt, S. Ganesamoorthy, I. Bhaumik, A. K. Karnal, P. K. Gupta, J. George J and K. Ranganathan,
   DAE-BRNS National Laser Symposium, MSID 3037 (2010).

YEAR---2007

1. “Effect of Pump Spectra on Single Longitudinal Mode Performance”, 
   J. George, S. M. Oak,
   DAE-BRNS National Laser Symposium, 116 (2007).
   
   
2. “Effect of first oscillating mode location drift on single longitudinal mode performance”,
   J. George, S. M. Oak,
   DAE-BRNS National Laser Symposium, 37 (2007).

YEAR---2006

1. “Demonstration of 3.4mW SLM UV Laser at 266nm by Resonant Cavity Doubling of Diode Pumped Nd:YVO4/KTP Green Laser”,
   J. George, R. Sehgal, A. K. Nath,
   National Laser Symposium, 45 (2006).

YEAR---2004

1. “A novel technique to generate more than 250mW tunable single mode IR Laser  at 1064nm from diode-end-pumped Nd:YVO4 crystal”, 
   J. George, J. P.  Xavier, V. K. Agnihothri, T. P. S. Nathan,
   National Laser Symposium, 158 (2004).
   
   
2.  “Development of control electronics for frequency locking of external resonant ring cavity to a laser beam using Hansch-Couillaud Scheme”,
   J. George, M. Saxena, V. K. Agnihotri, J. P.  Xavier, T. P. S. Nathan,
   National Laser Symposium, 161 (2004).

YEAR---2003

1. “Characterization of laser-diode end-pumped intracavity frequency doubled, passively Q-switched and modelocked Nd:YVO4 laser”,
   P. K. Mukhopadhyay, K. Ranganathan, S. K. Sharma, A. Kuruvilla A., P. K. Gupta, J. George, T.P.S. Nathan,
   National Laser Symposium, 137 (2003).
   
   
2. “A Study of Stable Single-Longitudinal Mode generation in fiber coupled diode-end-pumped Nd:YVO4 with short absorption depth:  Effect of pump spectra, doping concentration and LD polarization”,
   J. George, V. K. Agnihothri, K. Antony, K. Ranganathan, P. K. Mukhopadhyay,  T. P. S. Nathan,
   National Laser Symposium, 117 (2003).
   
   
3.  “Stable 100mW of Single-Longitudinal, Single-Transverse, Single-Polarization mode IR Laser  at 1064nm from diode-end-pumped Nd:YVO4 a-cut crystal with short-absorption-depth”,
   J. George, V. K. Agnihothri, K. Ranganathan, P. K. Mukhopadhyay, T. P. S. Nathan,
   National Laser Symposium, 119 (2003).
   
   
4. “Stable intracavity frequency doubled diode pumped Nd:YAG laser with more than 10W of average power at 532 nm”,
   P. K. Mukhopadhyay, K. Ranganathan, N. Muthukumaran, S. K. Sharma, A. Kuruvilla, J. George, T. P. S. Nathan,
   National Laser Symposium, 139 (2003).
   
   
5.  “Characterization of laser diode end-pumped intracavity frequency doubled, passively Q-switched and modelocked Nd:YVO4 laser”,
   P. K. Mukhopadhyay, K. Ranganathan, S. K. Sharma, A. Kuruvilla, P. K. Gupta, J. George, T. P. S. Nathan,
   National Laser Symposium, 137 (2003).

YEAR---2002

1. “Degree of stability and its measurement:  Application to a diode pumped solid state laser”,
   J. George, K. Ranganatnan, P. K. Mukhopadhyay, S. K. Sharma and T. P. S. Nathan,
   National Laser Symposium, 33 (2000).
   
   
2. “11.3 watts of CW IR power at 1064nm from a diode end pumped Nd:YVO4 laser”,
   P. K. Mukhopadhyay, K. Ranganathan, N. Muthukumaran, J. George, S. K. Sharma, P. K. Gupta and T. P. S. Nathan,
   National Laser Symposium, 142 (2000).
   
   
3. “Experimental determination of thermo-optic coefficient of a-axis cut Nd:GdVO4 crystal”,
   P. K. Mukhopadhyay, K. Ranganathan, N. Muthukumaran, J. George, S. K. Sharma, P. K. Gupta and T. P. S. Nathan,
   National Laser Symposium, 148 (2000).
   
   
4. “Characterization of a diode pumped Nd:YVO4 laser passively Q-Switched with GaAs”,
   P. K. Mukhopadhyay, K. Ranganathan, D. Kappda, J. George, S. K. Sharma and T. P. S. Nathan,
   National Laser Symposium, 151 (2000).
   
   
5. “Passive Q-Switching of axis cut nd:YVO4 laser using Cr:YAG under high power CW laser pumping:  Effect of initial transmission”,
   P. K. Mukhopadhyay, K. Ranganathan, D. Kappda, J. George, S. K. Sharma and T. P. S. Nathan,
   National Laser Symposium, 153 (2000).

YEAR---2001

1. "Nd:CNGG laser under high power diode laser pumping",
   P. K. Mukhopadhyay, J. R. Gangrah, M. V. Rishi, K. Ranganathan, S. K. Sharma, J. George, N. Muthukumaran, K. N. Srivastava and T.P.S. Nathan,
   National Laser Symposium, 5 (2000).
   
   
2. "High power Diode pumped intracavity doubled GREEN Laser using external Harmonic Mirror Coupled Resonator",
   J. George, A. K. Thipsay, K. Ranganatnan, P. K. Mukhopadhyay, S. K. Sharma and T. P. S. Nathan,
   National Laser Symposium, 7 (2000).
   
   
3. "An alternative method to determine fractional heat load in solid state laser material: Application to Nd3+ doped YVO4 crystal",
   P. K. Mukhopadhyay, J. George, K. Ranganathan, S. K. Sharma, R. K. Jain, K. K. Pant and T. P. S. Nathan,
   National Laser Symposium, 9 (2000).
   
   
4. "Effect of absorbed pump power on output beam quality of monolithic microchip lasers",
   P. K. Mukhopadhyay, K. Ranganathan, J. George, G. Mundra and T. P. S. Nathan,
   National Laser Symposium, 11 (2000).
   
   
5. "Effect of Nd3+ concentration on cw and pulsed performance of fiber -coupled diode laser pumped Nd:YVO4 laser at 1064 nm",
   P. K. Mukhopadhyay, J. George, K. Ranganathan, S. K. Sharma, P. Gaure and T. P. S. Nathan,
   National Laser Symposium, 13 (2000).
   
   
6. "Polarization characteristics of the output beam from a dual crystal single cavity Nd:YVO4 laser",
   P. K. Mukhopadhyay, J. George, K. Ranganathan, C. V. Pawar, S. K. Sharma, P. K. Gupt and T. P. S. Nathan,
   National Laser Symposium, 15 (2000). 
   
   
7. “Third Harmonic Generation of Super Gaussian Nd:YAG Laser”,
   P. Sundar, J. George, P. Shryner, S. C. Vishwakarma and T. P. S. Nathan,
   National Laser Symposium, 251 (2000).

YEAR---2000

1. “Performance characterization of acousto-optically Q-switched Nd:YVO4 micro laser”,
   P. K. Mukhopadhyay, J. George, S. K. Sharma, B. N. Upadhyay and T. P. S. Nathan,
   National Laser Symposium, 43(2000).
   
   
2. “Temperature controlled waveplating in KTP crystal”,
   J. George, K. Ranganathan, P. K. Mukhopadhyay, S. K. Sharma and T. P. S. Nathan,
   National Laser Symposium, 26 (2000).
   
   
3. “Q-switching of diode laser pumped intra-cavity doubled Nd:YVO4 with acousto-optic modulator”,
   J. George,  P. K. Mukhopadhyay and T. P. S. Nathan,
   National Laser Symposium, 41 (2000).
   
   
4. “Sensor Characterization of 1W hand held laser power meter”,
   D. K. Kohli, P. K. Mukhopadhyay, J. George, V. P. Bhanage, D. K. Agarwal, A. G. Bhujle and T. P. S. Nathan,
   National Laser Symposium, 270 (2000).

YEAR---1999

1.  “Measurement of st product of Nd:KGW crystal by laser comparison method”,
   D. K. Kohli, P. K. Mukhopadhyay, J. George, S. K. Sharma, R. Kapoor and  T. P. S. Nathan,
   National Laser Symposium, 112 (1999).
   
   
2. “Direct measurement of st product of Nd:GdVO4 crystal in monolithic laser Configuration”,
   P. K. Mukhopadhyay, J. George, S. K. Sharma and R. Kapoor,
   National Laser Symposium, 118 (1999).
   
   
3. “Measurement of thermal lens in Nd:KGW and Nd:GdVO4 crystal”,
   J. George, P. K. Mukhopadhyay, D. K. Kohli, S. K. Sharma, R. Kapoor and T. P. S. Nathan.,
   National Laser Symposium, 106 (1999).

YEAR---1998

1.  “An Alternate Approach to calculate the overlap efficiency”;
   R. Kapoor, P. K. Mukhopadhyay and J. George,
    National Laser Symposium, 191(1998)
   
   
2. “High Efficiency Nd: YVO4/KTP Green Laser pumped by Laser Diode”,
   J. George, P. K. Mukhopadhyay, S. K. Sharma and R. Kapoor,
   National Laser Symposium, 3 (1998).
   
   
3. “An alternative approach to determine the spot size of a multi-mode laser beam”; 
   R. Kapoor, J. George and P. K. Mukhopadhyay,
   National Laser Symposium, 193 (1998).

YEAR---1997

1. “Laser Diode Power Supply”,
   J. George, V. Prakash, R. Kapoor,
   National Laser Symposium, 137 (1997)
   
   
2. “Wavelength Tuning of a Laser Diode using Thermoelectric Cooler”,
   J. George, V. Prakash, P. K. Mukhopadhyay, S. K. Sharma, R. Kapoor,
   National Laser Symposium, 135 (1997)
   
   
3. “Diode Laser Pumped microchip Nd:GdVO4 Laser”,
   P. K. Mukhopdhyay, J. George, S. Kumar Sharma, R. Kapoor, D. D. Bhawalkar,
   National Laser Symposium, 49 (1997).
   
   
4. “Intracavity doubling of CW Diode pumped Nd: YVO4 lasers with KTP”,
   J. George, P. K. Mukhopadhyay and R. Kapoor,
   National Laser Symposium, 92 (1997).
   
   
5. “A comparison between Nd: YVO4 and Nd: GdVO4 microchip lasers”,
   P. K. Mukhopadhyay, J. George, S. K. Sharma and R. Kapoor,
   National Laser Symposium , 90 (1997).
   
   
6. “A new method to measure thermal lens in microchip lasers”,
   R. Kapoor, P. K. Mukhopadhyay, J. George, S. K. Sharma and H. S. Vora,
   National Laser Symposium, 68 (1997).

YEAR 2013

1. M Tech Dissertation (under my supervision/Co-guide),
   “Study of Cr: Forsterite Based Ultrafast Laser system”, by Priyanka Thakur,
    submitted to SGSITS, 101 pages (2013)

 YEAR---2012

1. “Fiber laser pumped Cr:F based femto- second laser”,
   J. George, K. S. Bindra and S. M. Oak,
   RRCAT Newsletter  25(1), 28 (2012)

YEAR---2008

1. “A Study of diode pumped solid state lasers”,
    J. George,
   KIRAN 19 (1), 2 (2008)
   
   
2. “A Study of diode pumped solid state lasers”,
   J. George,
   RRCAT Newsletter 21 (2), 16 (2008)

YEAR---2007

1. “A study of diode pumped solid state lasers”,
   by J.George,
   Thesis submitted to Indian Institute of Technology (IIT) Bombay, (2007).
   
   
2. M Tech Dissertation (under my supervision/Co-guide),
   “ Development of SLM, UV Laser by resonant cavity doubling”,
   by R. Sehgal, submitted to Devi Ahilya Vishwa Vidhyalaya (DAVV), Indore (2007)

YEAR---2005

1. M Tech Dissertation(under my supervision/Co-guide),
   “ Design and development of high power end-pumped DPSS SLM Laser at 1064 nm using Nd:YVO4 ”,
   by J. P. Xavier, submitted to Univ. of Pune,  (2005 )

 YEAR---2002

1.  “Diode Pumped Solid State Lasers”,
   J. George,
   Kiran 13(1), 38(2002)  &  13(2),  2 (2002)

 YEAR---2010

1. “Energy/Power Measurement”,
   Tutorial by Jogy George at BARC Mumbai,  Jan (2010)

YEAR---2002

1. “Diode Pumped Solid State Lasers”,
   Invited by Talk by Jogy George
   at National Laser Symposium, Abstracts p 5, (2002)

YEAR---2001

1. “Diode Pumped Solid State Lasers and Intracavity Second Harmonic Generation”,
   Seminar #13 of  CAT Indore,
   J. George, May 23 (2001).