Lei Huang

Research on controlling thermal deformable mirror’s influence functions via manipulating thermal fields

For thermal deformable mirrors (DMs), the thermal field control is important because it will decide aberration correction effects. In order to better manipulate the thermal fields, a simple water convection system is proposed. The water convection system, which can be applied in thermal field bimetal DMs, shows effective thermal fields and influence-function controlling abilities. This is verified by the simulations and the contrast experiments of two prototypes: one of which utilizes air convection, the other uses water convection. Controlling the thermal fields will greatly promote the influence-function adjustability and aberration correction ability of thermal DMs.

Experimental investigation of the deformable mirror with bidirectional thermal actuators

A deformable mirror with actuators of thermoelectric coolers (TECs) is introduced in this paper. Due to the bidirectional thermal actuation property of the TEC, both upward and downward surface control is available for the DM. The response functions of the actuators are investigated. A close-loop wavefront control experiment is performed too, where the defocus and the astigmatism were corrected. The results reveal that there is a promising prospect for the novel design to be used in corrections of static aberrations, such as in the Inertial Confinement Fusion (ICF).

Electrochemical and XPS Investigation of Phthalocyanine Oligomer Sulfonate as a Corrosion Inhibitor for Iron in Hydrochloric Acid

A water soluble and metal free phthalocyanine oligomer sulfonate (H 2 PPC.(SO 3 Na) x ) has been synthesized and its corrosion inhibitive effect has been investigated by potentiodynamic measurement, ac impedance, and surface analysis. The potentiodynamic parameters show that H 2 PPc.(SO 3 Na) x can effectively reduce the corrosion current density and inhibit the corrosion of iron in 1 mol L -1 HCl at 313 K. The H 2 PPc·(SO 3 Na) x functions as a mixed type inhibitor with anodic suppression outweighing the cathodic one. The ac impedance result, which is shown in the form of a compressed capacitive semicircle on complex plots, demonstrates that charge transfer resistance R ct increases with the increase in concentration of H 2 PPc·(SO 3 Na) x in acidic solution. The X-ray photoelectron spectroscopy (XPS) result indicates the presence of the electronic donor-acceptor between Fe atoms and front molecular orbital of H 2 PPc·(SO 3 Na) x , evidence that the forms an adsorption layer on iron surface via chemical adsorption to protect iron from erosion in acid.

Photochemical DNA cleavage by novel water-soluble sulfonated dihydroxy phosphorus(V) tetrabenzotriazacorrole.

The photosensitizing properties of a novel water-soluble phthalocyanine-like photosensitizer, sulfonated dihydroxy phosphorus(V) tetrabenzotriazacorrole {P(OH)(2)TBCS(n)}, have been reported. It is relevant for the use of this dye as photodynamic sensitizer. The compound exhibited significant photocleavage of supercoiled (SC) pUC19 DNA. The photooxygenation and photocleavage to DNA showed high efficiency in generating singlet oxygen.

New methods to achieve high sensitivity of objective lens actuator in optical disc system

In order to reduce the cross-coupled vibration and improve the driving sensitivity of lens actuator, in this paper, we present some important factors that affect this sensitivity and propose new methods that can be conveniently adopted for existing product lines. Experimental results verify the validity of these proposed methods.

Photophysical properties of sulfonated dihydroxy phosphorus(V) tetrabenzotriazacorrole.

The photosensitizing properties of a novel phthalocyanine analogue, sulfonated dihydroxy phosphorus(V) tetrabenzotriazacorrole [P(OH)2TBCSn] and a non-sulfonated one [P(OH)2TBC] are reported in this paper. Different from other phthalocyanine derivatives, P(OH)2TBCSn shows little aggregation in aqueous solution. The fluorescence quantum yield (PhiF) of P(OH)2TBCSn is lower than that of the non-sulfonated one. Studies of triplet state photophysics show that the presence of peripheral substituents on the macrocycle enhances the quantum yield of the triplet state. The sulfonated derivative, P(OH)2TBCSn, has a longer triplet lifetime (tauT = 0.234 ms) and higher singlet oxygen quantum yield (PhiDelta = 0.88) than P(OH)2TBC. Together with the ground-state absorption properties, the photosensitizing properties of the new compound suggest that it may be used as an excellent photosensitizer for photodynamic therapy (PDT).

Static Stability Analysis for a Novel Permanent Magnetic Suspension Laser Beam Scanner

Because of mechanical abrasion and heat consumption, excellent performance is difficult to achieve in traditional laser beam scanners, which depend on mechanical contacts and friction between transmission mechanisms. In this paper we present a novel type of laser beam scanner employing a permanent magnetic suspension structure to realize scanning without any friction. For this new scanner, static stability is fully analyzed for the critical magnetic suspension structure based on magnetic theory and three dimensional finite element method (3D-FEM) tools. Some important factor, which greatly influence the stability are also proposed; efficient methods of improving the static stability are presented accordingly. A comparison of four sample structures in a typical experiment verifies the validity of the analysis and these methods.

Adaptive interferometric null testing for unknown freeform optics metrology

We report an adaptive interferometric null testing method for overcoming the dynamic range limitations of conventional null testing approaches during unknown freeform optics metrology or optics manufacturing processes that require not-yet-completed surface measurements to guide the next fabrication process. In the presented adaptive method, a deformable mirror functions as an adaptable null component for an unknown optical surface. The optimal deformable mirrors shape is determined by the stochastic parallel gradient descent algorithm and controlled by a deflectometry system. An adaptive interferometric null testing setup was constructed, and its metrology data successfully demonstrated superb adaptive capability in measuring an unknown surface.

High-precision system identification method for a deformable mirror in wavefront control

Based on a mathematic model, the relation between the accuracy of the influence matrix and the performance of the wavefront correction is established. Based on the least squares method, a two-step system identification is proposed to improve the accuracy of the influence matrix, where the measurement noise can be suppressed and the nonlinearity of the deformable mirror can be compensated. The validity of the two-step system identification method is tested in the experiment, where improvements in wavefront correction precision as well as closed-loop control efficiency were observed.

Wavefront correction performed by a deformable mirror of arbitrary actuator pattern within a multireflection waveguide

The wavefront correction ability of a deformable mirror with a multireflection waveguide was investigated and compared via simulations. By dividing a conventional actuator array into a multireflection waveguide that consisted of single-actuator units, an arbitrary actuator pattern could be achieved. A stochastic parallel perturbation algorithm was proposed to find the optimal actuator pattern for a particular aberration. Compared with conventional an actuator array, the multireflection waveguide showed significant advantages in correction of higher order aberrations.