Dr. Julia Sheldakova
Sadovsky Institute of Geosphere Dynamics of Russian Academy of Sciences
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Academic Career Length
25Years (2002-Present)
(Calculated once Scilit publication data is synced: current year − year of first publication + 1)
Representative Publications
View All Publications1 February 2006 in Review of Scientific Instruments
Journal Article
YAYutaka Akahane
Yutaka Akahane
JMJinglong Ma
Jinglong Ma
YFYuji Fukuda
Yuji Fukuda
MAMakoto Aoyoma
Makoto Aoyoma
HKHiromitsu Kiriyama
Hiromitsu Kiriyama
KYKoichi Yamakawa
Koichi Yamakawa
+2
An improvement of laser-focused peak intensity has been achieved in a JAERI 100 TW Ti:sapphire chirped-pulse amplifier chain with a feedback controlled adaptive optics system operating at a 10 Hz repetition rate. The Strehl ratio was enhanced to 0.8 by means of a Bimorph deformable mirror with a Shack-Hartmann wave-front sensor. Measurements of optical parameters of the laser pulse and an experimental tunneling ionization yield of helium have practically confirmed focusing to ultrarelativistic intensities of over within 16% accuracy.
30 November 2020 in Optics Express
Journal Article
Кудряшов Алексей ВалерьевичARAlexey L. Rukosuev
Alexey L. Rukosuev
ANAlexander N. Nikitin
Alexander N. Nikitin
IGIlya V. Galaktionov
Ilya V. Galaktionov
Julia SheldakovaProblems of constructing an adaptive optical system intended for correcting the wavefront of laser radiation that has passed through a turbulent atmosphere are considered. To ensure high-quality wavefront correction, the frequency of the discrete system should be at least 1 kHz or more. This performance can be achieved by using FPGA as the main control element of the system. The results of a laboratory experiments of the laser beam phase fluctuations caused by turbulence, produced by the airflow of a fan heater, correction by means of the FPGA-based adaptive optical system are presented. The system efficiency was evaluated at various correction frequencies up to 1875 Hz.
23 June 2010 in Quantum Electronics
Journal Article
AAA G Aleksandrov
A G Aleksandrov
VZValentina Zavalova
Valentina ZavalovaКудряшов Алексей ВалерьевичARA L Rukosuev
A L RukosuevJulia SheldakovaPRP N Romanov
P N Romanov +1
26 July 2019 in Applied Optics
Journal Article
Vladimir ToporovskyКудряшов Алексей ВалерьевичVSVadim Samarkin
Vadim Samarkin
Julia SheldakovaARAlexey Rukosuev
Alexey Rukosuev
DPDanila Pshonkin
Danila Pshonkin
+1
This paper presents a new development of small-diameter, high-spatial-resolution, semipassive bimorph deformable mirrors to be used in different imaging systems. To manufacture the small control elements, laser engraving technology is used. An ultrasonic welding technique to connect the wires to the electrodes (actuators) is applied for this kind of mirror. The initial flatness of the mirror surface equals 0.33 μm (P-V) due to the use of substrate polishing technology after gluing the glass substrate to a piezo disk. We present the main parameters of these wavefront correctors, such as the response functions of different electrodes, temporal behavior, and the ability to compensate for high-order aberrations.
Journal Article
Ilya GalaktionovANAlexander Nikitin
Alexander NikitinJulia SheldakovaVladimir ToporovskyКудряшов Алексей ВалерьевичThe rarely considered case of laser beam propagation and focusaing through the moderately scattering medium was researched. A phase-only spatial light modulator (SLM) with 1920×1080 pixel resolution was used to increase the efficiency of focusing of laser radiation propagated through the 5 mm layer of the scattering suspension of 1 µm polystyrene microbeads in distilled water with the concentration values ranging from 105 to 106 mm−3. A CCD camera with micro-objective was used to estimate the intensity distribution of the far-field focal spot. A Shack-Hartmann sensor was used to measure wavefront distortions. The conducted experimental research demonstrated the 8% increase in integral intensity and 16% decrease in diameter of the far-field focal spot due to the use of the SLM for laser beam focusing.
Journal Article
VSVadim Samarkin
Vadim SamarkinAAAlexander Alexandrov
Alexander AlexandrovIlya GalaktionovКудряшов Алексей ВалерьевичANAlexander Nikitin
Alexander NikitinJulia Sheldakova +2
The bimorph deformable mirror with a diameter of 320 mm, including 127 control electrodes, has been developed and tested. The flatness of the initial mirror surface of about 1 μm (P-V) was achieved by mechanically adjusting the mirror substrate fixed in the metal mount. To correct for the aberrations and improve the beam focusing in the petawatt Ti:Sa laser, the wide-aperture adaptive optical system with the deformable mirror and Shack–Hartmann wavefront sensor was developed. Correction of the wavefront aberrations in the 4.2 PW Ti:Sa laser using the adaptive system provided increases the intensity in the focusing plane to a value of 1.1 × 1023 W/cm2
About Me
Julia Sheldakova, Ph.D., lead researcher at the Institute of Geosphere Dynamics RAS. Graduated from Vladimir State University in 2000 (diploma project “Novel methods of diagnostic of laser beams” in applied mathematics). In 2000, she took professional training on laser physics at the M.V.Lomonosov Moscow State University. In 2007, she received her Ph.D. from M.V.Lomonosov Moscow State University (“Investigation and control for the spatial characteristics of a laser beam by means of adaptive optics”). She is a specialist in the field of laser beam shaping and control using adaptive optics. She is an SPIE community champion, chair of the international conference "Laser resonators, microresonators and beam control", Photonics West, San Francisco, CA, USA, and program committee member of the international conference "Optical Wireless and Fiber Power Transmission" (OWPT), OPIC, Yokohama, Japan.