Resonant mirror

Capstan imagesetters, the third common technology, slowly advance the film or paper across a flat surface. A single laser beam is scaimed across the width of the medium by a rotating polygon or resonant mirror. 

Figure 11. Resonant mirror sensor with angular modulation.

Cush R., Cronin J.M., Stewart W.J., Maule C.H., Molloy J., Goddard N. J., The resonant mirror a novel optical biosensor for direct sensing of biomolecular interactions, Part I Principle of operation and associated instrumentation, Biosensors and Bioelectronics 1993 8 347-353. 

Buckle, P. E. Davies, R. J. Kinning, T. Yeung, D. Edwards, P. R. Pollard Knight, D. Lowe, C. R., The resonant mirror A novel optical biosensor for direct sensing of biomelcular interactions. Part II Applications, Biosens. Bioelectron. 1993, 8, 355 363... 

Goddard, N. J. Pollard Knight, D. Maule, C., Real time biomolecular interaction analysis using the resonant mirror sensor, Analyst 1994, 119, 583 588... 

With the reflectivities R = — T and R2 = I — T2 oi the resonator mirrors, the intensity / of a wave in a passive resonator after a single round trip is given by / = R R2h = h exp(-y ), y being the reflection losses and /o the incident intensity. Taking into account that the losses are only due to the output coupler (that is, y = ka) and that the reflectivity of the output mirror is given byi 2 = 1 - 2 = 0.5, the population inversion density at threshold is given by... 

R. Cush, J. M. Cronin, W. J. Stewart, C. H. Maule, J. Molloy, and N. J. Goddard, "The Resonant Mirror A Novel Optical Biosensor for Direct Sensing of Biomolecular Interactions Part I Principle of Operation and Associated Instrumentation," Biosensors Bioelectronics 8, 347-354 (1993). 

Instrument, Dallas, TX), SPR spectroscope (Multiscop , Optrel GbR, Germany), Reichert SR7000 (Reichert Analytical Instruments, Depew, NY), and resonant mirror based lAsys (Thermo Labsystems, Cambridge, UK). 

Lathrop, A. A., Jaradat, Z. W., Haley, T., and Bhunia, A. K. (2003). Characterization and application of a Listeria monocytogenes reactive monoclonal antibody C11E9 in a resonant mirror biosensor. J. Immunol. Methods 281,119-128. 

Fig. 7. Experimental arrangement of a giant-pulse laser (Q-switching by dye solution). AM, active material (e.g. ruby crystal rod), F, flashlamp, Mj, 2, resonator mirrors, DC, dye cell...

The necessary pump powers can be achieved either by other lasers (e.g. nitrogen lasers, solid-state lasers or even focussed He-Ne- or Ar+-gas lasers) or by flash-lamps. The simplest practical arrangement is a square spectrophotometer cell, polished on all sides, containing the dye solution which is pumped by a nitrogen laser whose beam is focussed into a line parallel to and directly behind one of the cell windows. Then the Fresnel reflection from the two adjacent windows gives enough feedback in most cases, so that no additional resonator mirrors are needed and the dye laser oscillation starts. 

Kurtz and Giordmaine 79> were the first to observe stimulated Raman scattering at the polariton associated with the TO phonon at 630 cm-1 which was shifted to 497 cm-1 for 0° scattering excited with a Q-switched ruby laser. The corresponding phonon was also observed in this experiment. This can be explained by backward (180°) stimulated Raman scattering reflected from the laser resonator mirrors as confirmed by measurements of relative time of arrival at the spectrometer. 

Fig. 10 Different refractive-index-based sensors, a A grating coupler, where Ns, Nw and Nm are the refractive indexes of the substrate, the waveguide and the surrounding medium respectively, b A resonant mirror, where Nm, Nr and Nc are the refractive indexes of the medium, the resonant layer and the coupling layer...

For refractive-index-type sensors, the waveguide is intrinsically the sensing element, and then chemical processes are measured with the variations of the refractive index, n, of guided modes. The majority of the various sensor types and published configurations make use of grating couplers (Fig. 10a) [83,84], resonant mirrors (Fig. 10b) [52,86-89] or interferometric sensors (Fig. 11) as... 

Skladal, P., A. Deng, and V. Kolar (1999). Resonant mirror-based optical inununosensor application for the measurement of atrazine in soil. Anal. Chim. Acta, 399 29-36. 

Figure 15. Deconvoluted ESI spectrum derived from the raw data for ricin. (Reprinted from Analytical Biochemistry, 279, Despeyroux etal., Characterization of Ricin Heterogeneity by Electrospray Mass Spectrometry, Capillary Electrophoresis, and Resonant Mirror, pp. 23-36 (2000), with permission from Elsevier)...

D. Despeyroux, N. Walker, M. Pearce, M. Fisher, M. McDonnell, S.C. Bailey, G.D. Griffiths and P. Watts, Characterization of ricin heterogeneity by electrospray mass spectrometry, capillary electrophoresis, and resonant mirror, Anal. Biochem., 279, 23-36 (2000). 

Figure 2-20 (A) Gas cell with external resonating mirrors. (B) Capillary cell for liquids. (C) Cylindrical cell for liquids. (D) KBr pellet for solid samples.

A chemical sensor is a device that transforms chemical information into an analytically useful signal. Chemical sensors contain two basic functional units a receptor part and a transducer part. The receptor part is usually a sensitive layer, therefore a well founded knowledge about the mechanism of interaction of the analytes of interest and the selected sensitive layer has to be achieved. Various optical methods have been exploited in chemical sensors to transform the spectral information into useful signals which can be interpreted as chemical information about the analytes [1]. These are either reflectometric or refractometric methods. Optical sensors based on reflectometry are reflectometric interference spectroscopy (RIfS) [2] and ellipsometry [3,4], Evanescent field techniques, which are sensitive to changes in the refractive index, open a wide variety of optical detection principles [5] such as surface plasmon resonance spectroscopy (SPR) [6—8], Mach-Zehnder interferometer [9], Young interferometer [10], grating coupler [11] or resonant mirror [12] devices. All these optical... 

Fig. 4. Diagram of a cavity dumped, passively mode-locked dye laser. In this version, the saturable absorber is in a free flowing dye stream. In more recent experiments, the saturable absorber flows in contact with a 100% reflectivity resonator mirror (see text).

By using a resonant mirror biosensor, the binding between YTX and PDEs from bovine brain was studied. The enzymes were immobilized over an aminosilae surface and the association curves after the addition of several YTX concentrations were checked. These curves follow a typical association profile that fit a pseudo-first-order kinetic equation. From these results the kinetic equilibrium dissociation constant (K ) for the PDE-YTX association was calculated. This value is 3.74 p,M YTX (Pazos et al. 2004). is dependent on YTX structure since it increases when 44 or 45 carbons (at C9 chain) group. A higher value, 7 p,M OH-YTX or 23 p,M carboxy-YTX, indicates a lower affinity of YTXs analogues by PDEs. 

Pazos, M.I, Alfonso, A., Vieytes, M., Yasumoto, T, and Botana, L. 2004. Resonant mirror biosensor detection method based on yessotoxin-phosphodiesterase interactions. Analytical Biochemestry 335, 112—118. 

Fig. 11.3. Scheme for monitoring the breakthrough of a binding protein from a chromatographic column using the resonant mirror as affinity sensor system. 

Waveguide-SPR Resonant mirror Grating coupler Mach-Zehnder interferometer Differential mode interferometer Young interferometer... 

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