Holographic recording in a suspension of bacteriorhodopsin D96N with optically controllable response time

<title>Spectroscopic diagnostics of bacteriorhodopsin nonlinear photoresponse</title>

“…(15) with X = 633 nm and u = 1,3. Besides, the mentioned values f3 and -y are close to calculated from Eqs (9),(15). with CX = 7 cm', q -0,8', c = 0,4 i03 mol/cm3: Ycal 4 mm/mJ, f3cai 0,35 lO mm2/mJ.…”

“…This correlation is described by the following equation The relation between light-induced absorption coefficient Aa and refractive index An for Lorenz shape of the absorption spectrum is written as AnIAa = (XI4it) uQ), (15) u(X) &X/AX, (16) where ct is the linear absorption coefficient, q is quantum efficiency of the primary photoreaction, N is BR molecules concentration, X is the wavelength shift from the center of the absorption curve, AX is the halfwidth of the absorption curve. It is worth note that the experimentally obtained rate 3/y 0,9 i0 is in good accordance with the value If the absorption spectrum differs from the Lorenz shape, e.g.…”

“…if the initial photon starts the multystepped chemical reaction with several outputs, then Eq. (15) is not correct, and other expressions should be used for An calculation, for example it could be Kramers-Kronig relations'7 in the differential form , 2,3032F2 2K JJ() R) An(2,R)=-2r2 V•P•J2,2 d2, (17) where Aa(k,R), An(X,R) are light induced variations of absorption coefficient and refractive index, 2,303 arises from the optical density definition D = ig 'r, t is transparency, XH and XK are the wavelengths which restrict the spectral interval of Aa(X,R) variations, v.p. means the main value ofthe integral.…”