How Shaped Light Discriminates Nearly Identical Biochromophores

Abstract

We present a general mechanism for successful discrimination of spectroscopically indistinguishable biochromophores by shaped light. For this purpose we use nonadiabatic dynamics in excited electronic states in the frame of the field-induced surface hopping method driven by the experimentally shaped laser fields. Our findings show that optimal laser fields drive low-frequency vibrational modes localized in the side chains of two biochromophores, thus selecting the parts of their potential energy surfaces characterized by different transition dipole moments leading to different ionization probabilities. The presented mechanism leads to selective fluorescence depletion which serves as a discrimination signal. Our findings offer a promising perspective for using optimally shaped laser pulses in bioanalytical applications by increasing the selectivity beyond the current capability.

Towards controlling molecular motions in fluorescence microscopy and optical trapping: a spatiotemporal approach

“…fluorescence up-conversion [14], fluorescence Kerr gating [15] and stimulated emission [16,17]. Alternatively, quantum (coherent) control methods [18][19][20] with laser pulse shaping [21] have been used for selective excitation of fluorophores to differentiate nearly identical fluorophores in condensed phase [22][23][24]. Such approaches have also been extended to applications in fluorescence microscopy [25][26][27][28] (and also other microscopic techniques, e.g.…”

Discriminating Biomolecules with Coherent Control Strategies

“…The use of the optimal pulse shapes as input parameters for ab initio calculations, performed by the group of V. BonacicKoutecky, revealed the underlying mechanism of the discrimination process: [4] the optimal laser fields drive low-frequency vibrational modes localized in the side chains of two biochromophores, thus selecting the parts of their potential energy surfaces characterized by different transition dipole moments that, in turn, lead to variable ionization probabilities.…”

Robustness of controlled quantum dynamics

“…In the case of dipole parameter uncertainty, the E[µ pq ] and the σ 2 (µ pq ) correspond to the parameter estimates and variance of parameter estimates (8), in which Σ is assumed to be diagonal. While these pathways could be evaluated by multiple integration of the Dyson terms, this can be computationally taxing especially when a large number of Dyson terms are involved in the dynamics.…”

“…Here, the quantum control objective is typically to design an external electromagnetic field which coherently manipulates a quantum system from an initial state to a desired final state. The appropriate engineering of a control field has been implemented in various quantum settings leading to several important technological applications, such as selective bond dissociation of compounds [7], discrimination of similar biomolecules [8], real-time microscopy of biological systems [9], and quantum computing [10].…”