scholarly journals Influence of spherical aberration of the thermal lens on the mode profile of a large-volume TEM00-mode resonator

2008 ◽  
Vol 57 (3) ◽  
pp. 1704 ◽  
Author(s):  
Liu Chong ◽  
Ge Jian-Hong ◽  
Xiang Zhen ◽  
Chen Jun
Keyword(s):  
Large Volume ◽  
Thermal Lens ◽  
Spherical Aberration ◽  
Tem00 Mode ◽  
Mode Resonator

Research on Thermal Effect and Mode Properties of a Q-Switched Laser by Using Shack-Hartmann Wavefront Sensor

2011 ◽  
Vol 308-310 ◽  
pp. 1444-1447
Author(s):  
Xiang Zhang
Keyword(s):  
Thermal Lens ◽  
Matrix Theory ◽  
Second Harmonic ◽  
Spherical Aberration ◽  
Beam Quality ◽  
Wavefront Sensor ◽  
Wavefront Aberration ◽  
Output Beam ◽  
Lens Effect ◽  
Thermal Lens Effect

Results of an experimental and theoretical analysis of the proprerties of a LD pumped laser using a stable resonator and second harmonic conversion crystal are presented. The influence of thermal lens effect on laser output mode and beam quality has been discussed briefly by using the transfer matrix theory. In this paper, further experiment on the output beam quality of a LD pumped acousto-optic Q-switched laser has been also performed by adopting Shack-Hartmann wavefront sensor and Zernike mode reconstruction theory. Using this method, PV and RMS error of aberration wavefront, the first 35-order Zernike aberrations can be acquired. Furthermore, Strehl ratio curve of output beam and the distribution of circle energy can also be obtained by further calculation, so mode properities can be comprehensively understood. Experimental results show that the beam wavefront aberration is mainly concentrated in the first 15 orders of Zernike aberration, mainly including the defocus A3, the low-order astigmatism A4 and A5, the coma and spherical aberration because of the thermal-lens effect.

scholarly journals High Power CO2 Laser Using a Gauss-core Resonator for 6 kW Large-volume TEM00 Mode Operation.

1995 ◽  
Vol 23 (9) ◽  
pp. 767-778
Author(s):  
Yushi TAKENAKA ◽  
Shigeto TAKESHIMA ◽  
Junichi NISHIMAE ◽  
Masaki KUZUMOTO ◽  
Kenji YOSHIZAWA
Keyword(s):  
Co2 Laser ◽  
Large Volume ◽  
High Power ◽  
Mode Operation ◽  
Tem00 Mode

scholarly journals Telescopic resonators for large-volume TEM00-mode operation

1981 ◽  
Vol 13 (6) ◽  
pp. 493-507 ◽  
Author(s):  
D. C. Hanna ◽  
C. G. Sawyers ◽  
M. A. Yuratich
Keyword(s):  
Large Volume ◽  
Mode Operation ◽  
Tem00 Mode

Beam quality improvement by controlling thermal lens spherical aberration in an end-pumped Nd:YVO4laser

2018 ◽  
Vol 57 (9) ◽  
pp. 2245 ◽  
Author(s):  
Qiangqiang Yao ◽  
Yuan Dong ◽  
Qihan Wang ◽  
Guangyong Jin
Keyword(s):  
Quality Improvement ◽  
Thermal Lens ◽  
Spherical Aberration ◽  
Beam Quality

scholarly journals Large volume TEM00 mode operation of Nd : YAG lasers

1981 ◽  
Vol 37 (5) ◽  
pp. 359-362 ◽  
Author(s):  
D.C. Hanna ◽  
C.G. Sawyers ◽  
M.A. Yuratich
Keyword(s):  
Large Volume ◽  
Mode Operation ◽  
Yag Lasers ◽  
Tem00 Mode

CBED Shadow Images and Cs:Aberration Measurement

1982 ◽  
Vol 40 ◽  
pp. 696-697
Author(s):  
R. W. Carpenter ◽  
I.Y.T. Chan ◽  
J. M. Cowley
Keyword(s):  
Focal Point ◽  
Spherical Aberration ◽  
Optic Axis ◽  
Wide Angle ◽  
Caustic Surface ◽  
Convergent Beam

Wide-angle convergent beam shadow images(CBSI) exhibit several characteristic distortions resulting from spherical aberration. The most prominent is a circle of infinite magnification resulting from rays having equal values of a forming a cross-over on the optic axis at some distance before reaching the paraxial focal point. This distortion is called the tangential circle of infinite magnification; it can be used to align and stigmate a STEM and to determine Cs for the probe forming lens. A second distortion, the radial circle of infinite magnification, results from a cross-over on the lens caustic surface of rays with differing values of ∝a, also before the paraxial focal point of the lens.

Resolution Attainable With the Present Day STEM

1973 ◽  
Vol 31 ◽  
pp. 230-231 ◽  
Author(s):  
J. S. Wall ◽  
J. P. Langmore ◽  
H. Isaacson ◽  
A. V. Crewe
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Incident Beam ◽  
Scanning Transmission Electron Microscope ◽  
Aperture Size ◽  
Magnetic Lens ◽  
Peak Intensity ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Half Angle

The scanning transmission electron microscope (STEM) constructed by the authors employs a field emission gun and a 1.15 mm focal length magnetic lens to produce a probe on the specimen. The aperture size is chosen to allow one wavelength of spherical aberration at the edge of the objective aperture. Under these conditions the profile of the focused spot is expected to be similar to an Airy intensity distribution with the first zero at the same point but with a peak intensity 80 per cent of that which would be obtained If the lens had no aberration. This condition is attained when the half angle that the incident beam subtends at the specimen, 𝛂 = (4𝛌/Cs)¼

Experiments with a Quadrupole Octopole Corrector in a STEM

1977 ◽  
Vol 35 ◽  
pp. 90-91 ◽  
Author(s):  
V. Beck
Keyword(s):  
Lower Order ◽  
Spherical Aberration ◽  
Mechanical Alignment

Recently a number of experiments have been carried out on a STEM which included a multipole corrector for primary spherical aberration. The results of these experiments indicate that the correction of primary spherical aberration with magnetic multipoles is beset with very serious difficulties related to hysteresis.The STEM and corrector have been described previously. In theory, the corrector should cancel primary spherical aberration so that other aberrations limit the resolution. For this instrument, secondary spherical aberration should limit the resolution to 1 A at 50 kV. A thorough study of misalignment aberrations was made. The result of the study indicates that the octopoles must be aligned to 1000 A. Since mechanical alignment cannot be done to this accuracy, trim coils were built into the corrector in order to achieve the required alignment electrically. The trim coils are arranged to excite all the lower order moments of an element.

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