Quantitative imaging of complex samples by spiral phase contrast microscopy

Author(s): Stefan Bernet, Alexander Jesacher, Severin Fürhapter, Christian Maurer, and Monika Ritsch-Marte

Abstract:

“Recently a spatial spiral phase filter in a Fourier plane of a microscopic imaging setup has been demonstrated to produce edge enhancement and relief-like shadow formation of amplitude and phase samples. Here we demonstrate that a sequence of at least 3 spatially filtered images, which are recorded with different rotational orientations of the spiral phase plate, can be used to obtain a quantitative reconstruction of both, amplitude and phase information of a complex microscopic sample, i.e. an object consisting of mixed absorptive and refractive components. The method is demonstrated using a calibrated phase sample, and an epithelial cheek cell.”

Link to Publications Page

Publication: Optics Express
Issue/Year: Optics Express, Vol. 14, Issue 9, pp. 3792-3805, 2006
DOI: 10.1364/OE.14.003792

Synthesis of multiple collinear helical modes generated by a phase-only element

Author(s): Jiao Lin, Xiaocong Yuan, Shaohua H. Tao, and Ronald E. Burge

Abstract:

“Phase-only elements are generally more desirable than complex-amplitude-modulated elements not only because of the higher diffraction efficiency but the readier implementation and fabrication. A novel iterative algorithm is proposed for generating multiple helical modes by a single phase-only element. A superposition of four helical modes is demonstrated experimentally by using a spatial light modulator.”

Link to Publications Page

Publication: Journal of the Optical Society of America A
Issue/Year: JOSA A, Vol. 23, Issue 5, pp. 1214-1218, 2006
DOI: 10.1364/JOSAA.23.001214

Aberration correction in holographic optical tweezers

Author(s): Kurt D. Wulff, Daniel G. Cole, Robert L. Clark, Roberto DiLeonardo, Jonathan Leach, Jon Cooper, Graham Gibson, and Miles J. Padgett

Abstract:

“Holographic or diffractive optical components are widely implemented using spatial light modulators within optical tweezers to form multiple, and/or modified traps. We show that by further modifying the hologram design to account for residual aberrations, the fidelity of the focused beams can be significantly improved, quantified by a spot sharpness metric. However, the impact this improvement has on the quality of the optical trap depends upon the particle size. For particle diameters on the order of 1 µm, aberration correction can improve the trap performance metric, which is the ratio of the mean square displacement of a corrected trap to an uncorrected trap, in excess of 25%, but for larger particles the trap performance is not unduly affected by the aberrations typically encountered in commercial spatial light modulators.”

Link to Publications Page

Publication: Optics Express
Issue/Year: Optics Express, Vol. 14, Issue 9, pp. 4169-4174, 2006
DOI: 10.1364/OE.14.004169

Holographic optical trapping of aerosol droplets

Author(s): D. R. Burnham and D. McGloin

Abstract:

“We demonstrate the use of holographic optical tweezers for trapping particles in air, specifically aerosol droplets. We show the trapping and manipulation of arrays of liquid aerosols as well as the controlled coagulation of two or more droplets. We discuss the ability of spatial light modulators to manipulate airborne droplets in real time as well as highlight the difficulties associated with loading and trapping particles in such an environment. We conclude with a discussion of some of the applications of such a technique.”

Link to Publications Page

Publication: Optics Express
Issue/Year: Optics Express, Vol. 14, Issue 9, pp. 4175-4181, 2006
DOI: 10.1364/OE.14.004175