Differential near-field scanning optical microscopy with THz quantum cascade laser sources.
We have realized a differential Near-field Scanning Optical Microscope (NSOM) working with subwavelength resolution in the THz spectral region. The system employs a quantum cascade laser emitting at lambda approximately 105 microm as source, and the method, differently from conventional NSOM, involves diffracting apertures with size comparable to the wavelength. This concept ensures a higher signal-to-noise level at the expense of an additional computational step. In the implementation here reported lambda/10 resolution has been achieved; present limiting factors are investigated through finite difference time domain simulations.
Degl'Innocenti
R
R
NEST, CNR-INFM and Scuola Normale Superiore, Piazza San Silvestro 12, I-56127 Pisa, Italy. riccardo.deglinnocenti@sns.it
Montinaro
M
M
Xu
J
J
Piazza
V
V
Pingue
P
P
Tredicucci
A
A
Beltram
F
F
Beere
H E
HE
Ritchie
D A
DA
D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D054023:Lasers, Semiconductor; D008029:Lighting / Q000295:instrumentation*; D033401:Microscopy, Acoustic / Q000295:instrumentation*; D055069:Terahertz Imaging / Q000295:instrumentation*; D055053:Terahertz Radiation