We employ a supercontinuum (SC) illumination to image the high-pressure fuel sprays in the near-nozzle region. The effect of speckles in the images is significantly mitigated using the SC illumination to improve the identifiability of the microstructures in the spray. The microstructures in the near-nozzle region, i.e., lobes, holes, ligaments, and bridges, are clearly imaged for different fuel pressures and nozzle orifice diameters. The shadowgraphs captured in the experiments also show the spray cone angle of spray is strongly dependent on the injection pressures and nozzle orifice diameters.
We demonstrated heterodyned optical Kerr gate (HOKG) ballistic imaging of an object hidden behind a turbid medium with two Kerr media. The experimental results showed that when compared with using HOKG of common Kerr medium CS2, a higher spatial resolution of the imaging system can be obtained by using HOKG of tellurite glass, which more effectively compensates for the high spatial-frequency components of the objects.
We demonstrated two ballistic imaging for an object hidden behind turbid media using the optical Kerr gate (OKG) and spatial filtering (SF), respectively. The influence of the scattering parameters of the turbid media on the image contrast was investigated. The experimental results showed that the image contrast of the SF imaging decreased significantly with increasing optical density and scattering particle size of the turbid media. Compared to the SF imaging, the OKG imaging showed a higher and more stable image contrast as scattering photons in the optical gated imaging case were more effectively eliminated.
An instantaneous three-dimensional imaging technique using a chirped supercontinuum and an ultrafast optical Kerr gate, in which a sapphire plate and a TeO2-ZnO-Na2O oxide glass were used to generate the chirped supercontinuum and the ultrafast optical Kerr gate, respectively, is demonstrated. This technique is applicable to ultrafast shape measurement, such as shape imaging of moving objects, or imaging of laser-induced refractive index changes in transparent media.
To develop high nonlinear optical fibers for all-optical switching applications, 7.5 wt% AgNO3 was incorporated into
tellurite glasses with composition of
75TeO2-20ZnO-5Na2CO3 (TZN75) under precisely-controlled experimental
conditions to form 7.5Ag-TZN75 glass. Surface Plasmon resonance absorption peak of Ag nanocrystals embedded in
7.5Ag-TZN75 glass was found to center at 552 nm. By degenerated
four-wave mixing method, the non-resonant
nonlinear refractive index, n2, of 7.5Ag-TZN75 glass was measured to be 7.54×10-19 m2•W-1 at 1500 nm, about 3 times of
the reference TZN75 glass without any dopant and 27 times of the silicate glasses and fibers, and the response time is
about 1 picosecond.
An ultrafast optical Kerr gate (OKG) in femtosecond time scale was used to determine the scattering coefficients of intralipids, in which the BI2O3-B2O3-SiO2 oxide glass was employed as the Kerr medium. Because of the joint action of the time gate and a transient spatial gate that was induced in the Kerr materials by the gating beam, more precise scattering coefficients could be obtained. Our experimental results show that, for low turbid media, the scattering coefficients measured using the OKG method are similar to those measured using the collimated transmittance (CT) approach, while for highly turbid media, the results obtained using the OKG method are bigger than those using the CT approach.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.