Luminescence detection of open-shell transition-metal ions by photoinduced electron transfer controlled by internal charge transfer of a receptor.
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Crystallography, X-Ray↗
Biomedical subjects
Holger Müller
Publications and source records attributed to Holger Müller.
Control of CaCO3 crystallization by demixing of monolayers.
In this paper we describe how to template a demixed monolayer into a spatially patterned inorganic replica. For this purpose a new amphiphilic monomer was synthesized which can be polymerized both in solution and in the monolayer of a Langmuir-Blodgett (LB) trough. Since it inhibits the crystallization of CaCO3, it can be used--in combination with stearic acid (nucleation-promotor)--to control CaCO3 crystals formed under the monolayer. Investigations of the two-component monolayer (Langmuir isotherms and AFM measurements of transferred films) show--in the biphasic region--demixing in solid analogue stearic acid domains and the liquid analogue phase of the monomer. Crystallization of CaCO3 starts under the stearic acid domains whose size varies from less than 100 nm to several tens of micrometers. The addition of poly(acrylic acid) into the subphase hinders the three-dimensional growth of CaCO3 crystals from the monolayer into the solution. Thus, it becomes possible to transfer the pattern of the demixed domains into an inorganic replica of CaCO3.
Acrylic Resins↗
Phase-locked, low-noise, frequency agile titanium:sapphire lasers for simultaneous atom interferometers.
We demonstrate a laser system consisting of a >1.6 W titanium:sapphire laser that is phase locked to another free-running titanium:sapphire laser at a wavelength of 852 nm with a phase noise of -138 dBc/Hz at 1 MHz from the carrier, using an intracavity electro-optic phase modulator. The residual phase variance is 2.5 x 10(-8) rad2 integrated from 1 Hz to 10 kHz. This system can phase-continuously change the offset frequency within 200 ns with frequency steps up to 4 MHz. Simultaneous atom interferometers can make full use of this ultralow phase noise in differential measurements, where influences from the vibration of optics are greatly suppressed in common mode.
Journal Article↗
Active sub-Rayleigh alignment of parallel or antiparallel laser beams.
We measure and stabilize the relative angle of parallel and antiparallel laser beams to 5 nrad/(square root of)Hz resolution by comparing the phases of radio frequency beat notes on a quadrant photodetector. The absolute accuracy is 5.1 and 2.1 microrad for antiparallel and parallel beams, respectively, which is more than 6 and 16 times below the Rayleigh criterion.
Journal Article↗
Test of the isotropy of the speed of light using a continuously rotating optical resonator.
We report on a test of Lorentz invariance performed by comparing the resonance frequencies of one stationary optical resonator and one continuously rotating on a precision air bearing turntable. Special attention is paid to the control of rotation induced systematic effects. Within the photon sector of the standard model extension, we obtain improved limits on combinations of 8 parameters at a level of a few parts in 10(-16). For the previously least well known parameter we find [EQUATION: SEE TEXT]. Within the Robertson-Mansouri-Sexl test theory, our measurement restricts the isotropy violation parameter [EQUATION: SEE TEXT]. corresponding to an eightfold improvement with respect to previous nonrotating measurements.
Journal Article↗
Offset compensation by use of amplitude-modulated sidebands in optical frequency standards.
We present a general method for continuously measuring and compensating for offsets (due to residual amplitude modulation, parasitic resonances, or electronic offset voltages, for example) in frequency stabilization systems. The spectral power distribution of the oscillator waveform is modified by amplitude-modulated sidebands, and the error signal is corrected to null the induced periodic lock-point shifts. We demonstrate significant improvements to the frequency stability of standards based on cryogenic optical resonators and molecular iodine.
Journal Article↗
Modern Michelson-Morley experiment using cryogenic optical resonators.
We report on a new test of Lorentz invariance performed by comparing the resonance frequencies of two orthogonal cryogenic optical resonators subject to Earth's rotation over approximately 1 yr. For a possible anisotropy of the speed of light c, we obtain Delta(theta)c/c(0)=(2.6+/-1.7)x10(-15). Within the Robertson-Mansouri-Sexl (RMS) test theory, this implies an isotropy violation parameter beta-delta-1 / 2=(-2.2+/-1.5)x10(-9), about 3 times lower than the best previous result. Within the general extension of the standard model of particle physics, we extract limits on seven parameters at accuracies down to 10(-15), improving the best previous result by about 2 orders of magnitude.
Journal Article↗