Dr. Rick Gentilman Profile

Dr. Rick Gentilman

Engineering Fellow at Raytheon

SPIE Involvement:

Author

Publications (28)

Proceedings Article | 21 May 2011 Paper

Laser damage resistant anti-reflection microstructures in Raytheon ceramic YAG, sapphire, ALON, and quartz

Douglas Hobbs, Bruce MacLeod, Ernest Sabatino, Thomas Hartnett, Richard Gentilman

Proceedings Volume 8016, 80160T (2011) https://doi.org/10.1117/12.883272

KEYWORDS: YAG lasers, Sapphire, Thin films, Ceramics, Laser damage threshold, Etching, Laser induced damage, Thin film coatings, Antireflective coatings, Near infrared

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Proceedings Article | 28 April 2009 Paper

Onshore produced ceramic laser material development progress

J. C. Huie Imholt, T. Hartnett, R. Gentilman, S. R. Silberstein

Proceedings Volume 7302, 730213 (2009) https://doi.org/10.1117/12.818026

KEYWORDS: Ceramics, Er:YAG lasers, Nd:YAG lasers, Crystals, Laser development, Laser crystals, YAG lasers, Laser optics, Solid state lasers, Geometrical optics

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Proceedings Article | 10 May 2007 Paper

Domestically produced ceramic YAG laser gain material for high power SSLs

J. Huie, R. Gentilman, T. Stefanik

Proceedings Volume 6552, 65520B (2007) https://doi.org/10.1117/12.719397

KEYWORDS: Ceramics, Nd:YAG lasers, YAG lasers, Er:YAG lasers, Crystals, High power lasers, Geometrical optics, Laser development, Solid state lasers, Laser optics

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Proceedings Article | 2 May 2007 Paper

Nano-composite optical ceramics for infrared windows and domes

Todd Stefanik, Richard Gentilman, Patrick Hogan

Proceedings Volume 6545, 65450A (2007) https://doi.org/10.1117/12.719312

KEYWORDS: Nanocomposites, Ceramics, Domes, Missiles, Infrared radiation, Transparency, Sapphire, Mid-IR, Infrared materials, Resistance

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Proceedings Article | 26 April 2007 Paper

Ceramic Yb: YAG microchip laser

Eric Ostby, Richard Ackerman, Jean Huie, Richard Gentilman

Proceedings Volume 6346, 63460V (2007) https://doi.org/10.1117/12.737389

KEYWORDS: Ceramics, Crystals, Laser crystals, Laser scattering, Q switched lasers, Nd:YAG lasers, Continuous wave operation, Pulsed laser operation, Q switching, YAG lasers

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Proceedings Article | 12 May 2006 Paper

Recent advances in onshore produced ceramic laser gain materials

Jean Huie, Richard Gentilman, Todd Stefanik, Derrick Rockosi

Proceedings Volume 6216, 62160L (2006) https://doi.org/10.1117/12.673007

KEYWORDS: Ceramics, YAG lasers, Crystals, Ytterbium, Nd:YAG lasers, Transmittance, Geometrical optics, Neodymium, Absorption, Laser crystals

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Proceedings Article | 28 February 2006 Paper

Ceramic Yb:YAG microchip laser

Eric Ostby, Richard Ackerman, Jean Huie, Richard Gentilman

Proceedings Volume 6100, 610004 (2006) https://doi.org/10.1117/12.660179

KEYWORDS: Ceramics, Crystals, Laser crystals, Laser scattering, Nd:YAG lasers, Q switched lasers, Continuous wave operation, Pulsed laser operation, Q switching, Laser damage threshold

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Proceedings Article | 18 May 2005 Paper

Submicron-grained transparent yttria composites

Bernard Kear, Rajendra Sadangi, Vijay Shukla, Todd Stefanik, Richard Gentilman

Proceedings Volume 5786, (2005) https://doi.org/10.1117/12.602333

KEYWORDS: Plasma, Composites, Ceramics, Oxides, Transmittance, Nanocomposites, Solids, Particles, Mid-IR, Yttrium

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Proceedings Article | 18 May 2005 Paper

Characterization of transparent polycrystalline yttrium aluminum garnet (YAG) fabricated from nano-powder

Jean Huie, Richard Gentilman

Proceedings Volume 5786, (2005) https://doi.org/10.1117/12.606599

KEYWORDS: YAG lasers, Ceramics, Crystals, Absorption, Nd:YAG lasers, Laser crystals, Neodymium, Transmittance, Semiconductor lasers, Polishing

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Proceedings Article | 26 September 2003 Paper

Low-cost sapphire windows

Richard Gentilman, Patrick McGuire, Daniel Fiore, Kim Ostreicher, Joel Askinazi

Proceedings Volume 5078, (2003) https://doi.org/10.1117/12.488241

KEYWORDS: Sapphire, Glasses, Optical coatings, Transmittance, Polishing, Index matching antireflective coatings, Wavefronts, Mid-IR, Refractive index, Surface finishing

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Proceedings Article | 26 September 2003 Paper

Large-area sapphire windows

Richard Gentilman, Patrick McGuire, Daniel Fiore, Kim Ostreicher, Joel Askinazi

Proceedings Volume 5078, (2003) https://doi.org/10.1117/12.501435

KEYWORDS: Sapphire, Ceramics, Crystals, Solids, Zinc, Polishing, Roads, Standards development, Distortion, Mid-IR

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Proceedings Article | 14 August 2003 Paper

Enhanced-performance active fiber composites

Richard Gentilman, Kelley McNeal, Gerald Schmidt, Alessandro Pizzochero, George Rossetti

Proceedings Volume 5054, (2003) https://doi.org/10.1117/12.483898

KEYWORDS: Actuators, Ferroelectric materials, Composites, Electrodes, Ceramics, Sensors, Crystals, Temperature metrology, Aerospace engineering, Control systems

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SPIE Journal Paper | 1 December 2002

Characteristics strength and Weibull modulus of selected infrared-transmitting materials

Claude Klein, Richard Miller, Richard Gentilman

OE, Vol. 41, Issue 12, (December 2002) https://doi.org/10.1117/12.10.1117/1.1517578

KEYWORDS: Failure analysis, Sapphire, Zinc, Crystals, Polishing, Chemical vapor deposition, Infrared materials, Diamond, Glasses, Unattended ground sensors

Proceedings Article | 2 November 2001 Paper

Flexural strength of sapphire: measurements performed at SoRI, UMass, and UDRI

Claude Klein, Richard Gentilman

Proceedings Volume 4452, (2001) https://doi.org/10.1117/12.446895

KEYWORDS: Sapphire, Failure analysis, Polishing, Unattended ground sensors, Crystals, Ceramics, Surface finishing, Data modeling, Optical coatings, Interfaces

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The results of fracture testing are usuaJly documented in terms of a measured strength, M ? where designates the arithmetic average of the recorded peak stresses at failure, and io represents the standard deviation. This "strength" '7M does not provide an objective measure of the intrinsic strength since M depends on the test method and the size of the volume or the surface subjected to tensile stresses. In this paper, we take advantage of Weibull's the- ory of fracture for providing an improved description of the failure statistics of sapphire test specimens subjected to biaxial stresses. For that purpose, we make use of the results of "ring-on-ring" flexural testing that was carried out over a period of 18 years at mechanical test facilities operated by the Southern Research Institute (SoRI), the University of Massachusetts (UMass), and the University of Dayton Research Institute (UDRI). Experiments were conducted, at room temperature, on test specimens supplied by two vendors and included mechanically polished as well as compressively coated specimens in the form of planar disks of different crystallographic orientation. Since equibiaxial flexure testing has now been adopted as the preferred method for assessing the strength of ceramics, we describe the failure probability in terms of a characteristic strength—i. e. , the effective strength for a 1-cm2 uniformly stressed area—, which allows one to evaluate the effective strength under different experimental conditions if the Weibuil modulus is available. The characteristic strengths (oc) and Weibull moduli (m) are predicated on a two-parameter model and validate the applicability of the area scaling law. Specifically, we conclude that: (a) The characteristic strength of polished c-plane sapphire is of the order of 975 MPa (140 kpsi) and the Weibull modulus is close to 3.4. (b) The strength of r-plane sapphire is substantially lower (oc 550 MPa 80 kpsi), but so is the scatter (m 4.1). And (c) strongly adhering compressive coatings can augment the strength by as much as 60 %,in accord with predictions based on simple fracture-mechanical considerations.

Proceedings Article | 7 September 2001 Paper

Large-area edge-bonded flat and curved sapphire windows

Patrick McGuire, Brian Pazol, Richard Gentilman, Joel Askinazi, John Locher

Proceedings Volume 4375, (2001) https://doi.org/10.1117/12.439174

KEYWORDS: Sapphire, Glasses, Optical coatings, Polishing, Index matching antireflective coatings, Surface finishing, Zinc, Crystals, Roads, Wavefronts

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Proceedings Article | 25 October 2000 Paper

Large-area flat and curved sapphire window blanks

Brian Pazol, Patrick McGuire, Richard Gentilman, John Locher, Joel Askinazi

Proceedings Volume 4102, (2000) https://doi.org/10.1117/12.405304

KEYWORDS: Sapphire, Zinc, Polishing, Directed energy weapons, Surface finishing, Crystals, Roads, Wavefronts, Ceramics, Objectives

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Proceedings Article | 22 June 2000 Paper

Fabrication and experimental characterization of d31 telescopic piezoelectric actuators

Paul Alexander, Diann Brei, Weiguo Miao, John Halloran, Richard Gentilman, Gerald Schmidt, Patrick McGuire, John Hollenbeck

Proceedings Volume 3985, (2000) https://doi.org/10.1117/12.388825

KEYWORDS: Actuators, Prototyping, Fabrication, Ceramics, Ferroelectric materials, Polymers, Polymerization, Aluminum, Polymeric actuators, Solids

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Proceedings Article | 26 July 1999 Paper

High-strength edge-bonded sapphire windows

Richard Gentilman, Patrick McGuire, Brian Pazol, Joel Askinazi, Robert Steindl, John Locher

Proceedings Volume 3705, (1999) https://doi.org/10.1117/12.354633

KEYWORDS: Sapphire, Polishing, Wavefronts, Zinc, Surface finishing, Ceramics, Transmittance, Mid-IR, Infrared radiation, Diffusion

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Proceedings Article | 12 July 1999 Paper

Processing and application of solid state converted high-strain materials

Kelley McNeal, Craig Near, Richard Gentilman, Martin Harmer, Helen Chan, Adam Scotch, Venkat Venkataramani, Charles Greskovich

Proceedings Volume 3675, (1999) https://doi.org/10.1117/12.352807

KEYWORDS: Crystals, Ceramics, Solid state electronics, Solid state physics, Manufacturing, Transducers, Sapphire, Ultrasonography, Annealing, Roads

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Proceedings Article | 9 July 1999 Paper

Piezocomposite SmartPanels and SmartMounts for active control of noise and vibration

Daniel Fiore, Richard Gentilman, Robert Torri, Brian Houston, Robert Corsaro

Proceedings Volume 3674, (1999) https://doi.org/10.1117/12.351585

KEYWORDS: Sensors, Transducers, Actuators, Composites, Control systems, Ceramics, Smart materials, Active remote sensing, Ferroelectric materials, Acoustics

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Proceedings Article | 16 June 1998 Paper

Injection-molded PZT actuators

Craig Near, Gerald Schmidt, Kelley McNeal, Richard Gentilman

Proceedings Volume 3326, (1998) https://doi.org/10.1117/12.310646

KEYWORDS: Actuators, Ferroelectric materials, Acoustics, Ceramics, Vibration control, Transducers, Lithium, Metals, Electrodes, Lead

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Proceedings Article | 16 June 1998 Paper

Piezocomposite SmartPanels for active control of underwater vibration and noise

Richard Gentilman, Daniel Fiore, Robert Torri, James Glynn

Proceedings Volume 3326, (1998) https://doi.org/10.1117/12.310640

KEYWORDS: Sensors, Transducers, Actuators, Ferroelectric materials, Ceramics, Polymers, Vibration control, Electronics, Composites, Control systems

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Proceedings Article | 27 June 1997 Paper

Thermal shock resistance of convectively heated infrared windows and domes

Claude Klein, Richard Gentilman

Proceedings Volume 3060, (1997) https://doi.org/10.1117/12.277037

KEYWORDS: Domes, Bismuth, Missiles, Resistance, Heat flux, Thermography, Diamond, Infrared radiation, Zinc, Spinel

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The sudden exposure to a supersonic flight environment subjects a missile window, or missile dome, to intense convective heat loads stemming from the rise in temperature of the boundary layer. The thermal response of the window then results in temperature gradients through the thickness, which generate transient stresses that may exceed the tensile strength of the material, thus causing thermal shock induced fracture. Since most of the materials that possess favorable optical properties in the infrared (IR) are relatively weak brittle solids, the problem of selecting window/dome materials and assessing their performance on a fly-out trajectory requires a careful evaluation of the window's ability to withstand thermally induced shocks. In this context, it is essential to keep in mind that the transient stress intensity depends on the nature of the heat flow as characterized by the Biot number (Bi). The allowable heat flux depends not only on intrinsic material properties but also on the heat-transfer coefficient if the condition Bi greater than 1 holds, or the thickness of the window if the condition Bi less than 1 applies. In a first approximation, the thermal shock performance of a 'thick' window will be controlled by the figure of merit (FoM)_{Bi greater than 1} equals R_H, i.e., the Hasselman parameter for strong shocks; in a thermally thin regime, however, the appropriate figure of merit is (FoM)_{Bi less than 1} equals sigma_fⁿR'_H with n equals 1/2 for flat plates and n equals 2/3 for hemispherical shells, and not the Hasselman parameter R'_H for mild shocks. Judging from the results of thermal shock testing performed elsewhere, we conclude that in a laminar flow environment the allowable heat flux on a thermally thin IR dome can be expressed as follows: Q_lim equals 2R'_H/L, where L is the dome thickness. This expression provides a direct means of obtaining the Mach altitude failure line for a dome of given thickness and given radius, if the initial wall temperature is known. Furthermore, it then becomes straightforward to assess the thermal shock resistance capability of a thickness-optimized IR dome either in terms of the allowable heat load or, more simply, the allowable stagnation temperature.

Proceedings Article | 23 May 1997 Paper

1-3 piezocomposite SmartPanels

Daniel Fiore, Richard Gentilman, Hong Pham-Nguyen, William Serwatka, Patrick McGuire, Craig Near, Leslie Bowen

Proceedings Volume 3044, (1997) https://doi.org/10.1117/12.274692

KEYWORDS: Transducers, Sensors, Composites, Actuators, Ceramics, Ferroelectric materials, Polymers, Electrodes, Analytical research, Ferroelectric polymers

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Proceedings Article | 1 May 1996 Paper

Underwater evaluation of piezocomposite panels as active surfaces

Robert Ting, Thomas Howarth, Richard Gentilman

Proceedings Volume 2721, (1996) https://doi.org/10.1117/12.239128

KEYWORDS: Composites, Ceramics, Actuators, Sensors, Acoustics, Signal detection, Explosives, Smart structures, Polymers, Transducers

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Proceedings Article | 1 May 1996 Paper

1-3 piezocomposite smart panels for active surface control

Richard Gentilman, Daniel Fiore, Hong Pham-Nguyen, William Serwatka, Brian Pazol, Craig Near, Patrick McGuire, Leslie Bowen

Proceedings Volume 2721, (1996) https://doi.org/10.1117/12.239130

KEYWORDS: Ferroelectric materials, Transducers, Composites, Manufacturing, Sensors, Ceramics, Control systems, Actuators, Polymers, Array processing

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Proceedings Article | 26 April 1996 Paper

Coformed accelerometer-actuator composites using injection-molded PZT

Robert Corsaro, Joseph Klunder, Richard Gentilman, Daniel Fiore

Proceedings Volume 2779, (1996) https://doi.org/10.1117/12.237180

KEYWORDS: Actuators, Composites, Sensors, Transducers, Electrodes, Ferroelectric materials, Multispectral imaging, Active remote sensing, Acoustics, Manufacturing

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