title: Photoacoustic holographic imaging of absorbers embedded in silicone.
abstract: Light absorbing objects embedded in silicone have been imaged using photoacoustic digital holography. The photoacoustic waves were generated using a pulsed Nd:YAG laser, λ=1064  nm, and pulse length=12  ns. When the waves reached the silicone surface, they were measured optically along a line using a scanning laser vibrometer. The acoustic waves were then digitally reconstructed using a holographic algorithm. The laser vibrometer is proven to be sensitive enough to measure the surface velocity due to photoacoustic waves generated from laser pulses with a fluence allowed for human tissue. It is also shown that combining digital holographic reconstructions for different acoustic wavelengths provides images with suppressed noise and improved depth resolution. The objects are imaged at a depth of 16.5  mm with a depth resolution of 0.5  mm.
authors.affiliation: Division of Experimental Mechanics, Luleå University of Technology, SE-97187 Luleå, Sweden. erka@ltu.se
authors.forename: Erik
authors.initials: E
authors.lastname: Olsson
authors.forename: Per
authors.initials: P
authors.lastname: Gren
authors.forename: Mikael
authors.initials: M
authors.lastname: Sjödahl
mesh_terms: D000162:Acoustics; D000465:Algorithms; D004867:Equipment Design / Q000295:instrumentation; D006696:Holography / Q000295:instrumentation*; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D007834:Lasers; D012828:Silicones / Q000737:chemistry; D012867:Skin / Q000000981:diagnostic imaging; D014463:Ultrasonography
chemical_list: D012828:Silicones