Novel concepts of vertical-cavity laser-based optical traps for biomedical applications

Kroner, A.; May, Johanna Friederike; Kardosh, I.; Rinaldi, F.; Roscher, Hendrik; Michalzik, Rainer

doi:10.1117/12.662458

Cited by 6 publications

(23 citation statements)

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“…For comparison we also analyze a simple reference multimode VCSEL, Fig. 1(f [9]. The emission wavelength is around 850 nm.…”

Section: Device Structure and Simulation Methodsmentioning

confidence: 99%

“…1, the five investigated structures are illustrated: (a) A thick microlens VCSEL (the first single-mode microlens VCSEL reported in [2]), two thin microlens VCSELs for (b) Gaussian-shaped and (c) doughnut-shaped outputs (the new structures suggested in this paper), (d) a surface relief VCSEL, and (e) a polymer-microlens surface-relief VCSEL [9]. For comparison we also analyze a simple reference multimode VCSEL, Fig.…”

Section: Device Structure and Simulation Methodsmentioning

confidence: 99%

“…1. Schematic profiles of (a) a thick microlens VCSEL [2], (b) a thin microlens VCSEL for Gaussian-shaped emission, (c) a thin microlens VCSEL for doughnut-shaped emission, (d) a surface relief VCSEL, (e) a surface relief VCSEL with a polymer microlens [9], and (f) a reference multimode VCSEL.…”

Section: Device Structure and Simulation Methodsmentioning

confidence: 99%

“…Considering that a typical lithographic misalignment is ~1 µm, stable single mode operation can be obtained using the thin lens approach. The single mode strength of the thin lens approach was compared to a surface relief VCSEL (reference single mode device), a polymer-microlens surface-relief VCSEL suggested in [9] (reference optical tweezers device with Gaussian emission), and a plain VCSEL (reference multimode device): The device profiles are shown in Fig. 1.…”

Section: Thin Microlens Vcselsmentioning

confidence: 99%

“…Two challenges are to obtain Gaussianshaped high-power emission for the trapping of non-absorbing high-refractive-index particles [7], and to achieve doughnut-shaped high-power emission for the trapping of absorbing, lowrefractive-index, or metallic particles [8]. The first approach for the Gaussian-shaped emission, based on a polymer microlens and a surface relief VCSEL, improves the lateral trapping efficiency, but significantly degrades the side mode suppression ratio (SMSR) of higher order modes and the differential quantum efficiency [9]. Regarding the doughnutshaped output, the first compact approach using a photonic crystal surface emitting laser [10], demonstrates a good lateral trapping force, but its high threshold current of 65 mA and relatively low output power of 4 mW at 95-mA bias current need to be improved [11].…”

Section: Introductionmentioning

confidence: 99%

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Transverse-mode-selectable microlens vertical-cavity surface-emitting laser

et al. 2010

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Abstract:A new vertical-cavity surface-emitting laser structure employing a thin microlens is suggested and numerically investigated. The laser can be made to emit in either a high-power Gaussian-shaped single-fundamental mode or a high-power doughnut-shaped higher-order mode. The physical origin of the mode selection properties of the new structure is rigorously analyzed and compared to other structures reported in the literature. The possibility of engineering the emission shape while retaining strong single mode operation is highly desirable for low-cost mid-range optical interconnects applications as well as the compact optical trapping of highrefractive-index dielectric particles and low-refractive-index, absorbing, or metallic particles.

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“…For comparison we also analyze a simple reference multimode VCSEL, Fig. 1(f [9]. The emission wavelength is around 850 nm.…”

Section: Device Structure and Simulation Methodsmentioning

confidence: 99%

Section: Device Structure and Simulation Methodsmentioning

confidence: 99%

Section: Device Structure and Simulation Methodsmentioning

confidence: 99%

Section: Thin Microlens Vcselsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Transverse-mode-selectable microlens vertical-cavity surface-emitting laser

et al. 2010

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Optical particle manipulation by application-specific densely packed VCSEL arrays

et al. 2008

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Densely packed arrays of vertical-cavity surface-emitting lasers (VCSELs) are presented, serving as low-cost and small-sized laser sources in optical particle manipulation systems. A novel, self-aligned fabrication process enables both a pitch in the 20 µm m range and a selective surface etch for enhanced transverse single-mode emission. Homogeneous array performance and single-mode output powers of up to 3.8 mW are observed. By inserting the arrays into an optical tweezers setup with external optics, multiple optical traps are easily created. Non-mechanical particle translation by switching between individually addressable devices as well as continuous particle deflection in a one-dimensional optical lattice are demonstrated.

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Densely Packed VCSEL Arrays Tailored for Optical Particle Manipulation

Kroner

Rinaldi

Rosch

et al. 2007

2007 European Conference on Lasers and Electro-Optics and the International Quantum Electronics Conference

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Recently, the use of vertical-cavity surface-emitting lasers (VCSELs) as light sources for optical particle trapping and manipulation has gained increasing interest, owing to high beam quality, low cost and the possibility to fabricate two-dimensional, monolithic laser arrays (see Refs. in [1]). Also, typical emission wavelengths are in the near infrared spectral region, which is important for damage-free manipulation of biological material. However, mainly standard VCSEL arrays designed for data communication have been applied so far, which show a large pitch of typically 250 µm and necessitate the use of additional microlens arrays. Furthermore, for a drastic miniaturization of the trapping setup towards the so-called integrated optical trap, the typical multimode output beam profile of VCSELs is inappropriate [1]. Therefore, we have fabricated arrays of top-emitting VCSELs with pitches down to 24 µm and an only 2 µm wide gap between the devices. For enhanced single-mode emission, the inverted surface relief technique [1] was applied on some devices. The output facets then contain a shallow, circular etch in their center. To guarantee steep mesa etching and an accurate alignment of oxide aperture, p-contact ring and relief, a novel fabrication process has been developed, based on multiple resist layers. At first, relief and p-contact ring are structured within the same exposure step, so selfalignment is achieved. Afterwards, two subsequent resist steps with large alignment tolerance enable selective wetchemical relief etching and metallization. Finally, the p-contact metal serves as mask for reactive ion etching of the mesa, such that the following oxidation step leads to a self-aligned oxide aperture. In Fig. 1, a scanning electron microscope (SEM) image of an array with 24 µm pitch and 3.4 µm surface relief diameter is presented, showing almost vertical mesa edges and exact alignment. The process is completed by surface passivation and bond pad metallization. Fig. 2 Operation characteristics of an array containing 15 individual devices without relief (left) and of three relief devices driven in parallel (right). The inset shows the optical spectra of all three devices at 30 mA.The left side of Fig. 2 presents the output characteristics of 15 individually addressable devices forming an array with 8 µm oxide apertures but without relief. Threshold currents of around 1.6 mA and maximum multimode output powers of about 8 mW with only minor variations are observed. Since we plan to implement an optical particle sorting scheme where an individual addressing of lasers is not required [2], also arrays with devices connected in parallel were fabricated in order to decrease the number of contacts significantly. The right side of Fig. 2 shows the light versus current curve of three jointly lasing devices, which have a 6 µm wide oxide aperture and 3.4 µm relief diameter. A mean threshold current of 1.7 mA and a high maximum output power of 3.8 mW for each device can be deduced. The inset shows the optical spectra of all ...

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Novel concepts of vertical-cavity laser-based optical traps for biomedical applications

Cited by 6 publications

References 0 publications

Transverse-mode-selectable microlens vertical-cavity surface-emitting laser

Transverse-mode-selectable microlens vertical-cavity surface-emitting laser

Optical particle manipulation by application-specific densely packed VCSEL arrays

Densely Packed VCSEL Arrays Tailored for Optical Particle Manipulation

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