Observed Dielectric Waveguide Modes in the Visible Spectrum*

Snitzer, E.; Osterberg, Harold

doi:10.1364/josa.51.000499

Cited by 137 publications

(27 citation statements)

References 3 publications

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“…The nature of the modes depends crucially on all the material factors of shape, optical parameters of the media, angle of incidence and so on. Modes have been demonstrated not only in optical fibre models (Snitzer & Osterberg 1961) but also, if only indirectly, in actual mammalian retina preparations (Enoch 1963). …”

Section: Guiding Of Light Into Receptorsmentioning

confidence: 99%

Directional sensitivity of the retina: 75 years of Stiles–Crawford effect

2008

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The reduction of the brightness when a light beam's entry into the eye is shifted from the centre to the edge of the pupil has from the outset been shown to be due to a change in luminous efficiency of radiation when it is incident obliquely on the retina. The phenomenon is most prominent in photopic vision and this has concentrated attention on the properties of retinal cones, where responsibility has yet to be assigned to factors such as differences in shape, fine structure and configuration, and membrane anchoring of photopigment molecules. Geometrical optics and waveguide formulations have been applied to the question of how light is guided in receptors, but details of their geometry and optical parameters even if they become available will make calculations complex and of only moderate generality. In practice, the diminution of oblique light helps visual performance by reducing deleterious influence of ocular aberrations and of glare caused by light scattering when the pupil is wide. Receptor orientation can come into play in ocular conditions due to mechanical disturbance and has been shown to have potentiality as a tool for clinical diagnosis. Currently, open questions include microanatomical and molecular differences between rods and cones, the coupling of the optical image of the eye with the transducing apparatus in the photoreceptors, possible phototropism and more convincing methods of estimating the actual spatial distribution of photon events as it affects visual resolution.

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Section: Guiding Of Light Into Receptorsmentioning

confidence: 99%

Directional sensitivity of the retina: 75 years of Stiles–Crawford effect

2008

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“…For cylindrically symmetric VCSEL cavity, its TE, TM, HE and EH cavity modes [2,3] may be grouped into linearly polarized transverse LP ij modes [4]. In this notation, the i th subscript indicates the number of node planes in the azi− muthal direction and the j th one -the number of peaks in the radial direction.…”

Section: Vcsel Mode Selectivitymentioning

confidence: 99%

Current spreading modification to enhance single-fundamental-mode VCSEL operation at higher temperatures

Sarzała

Nakwaski

2011

Opto-Electronics Review

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Continuous-wave (CW) performance of modern oxide-confined (OC) vertical-cavity surface-emitting diode lasers (VCSELs) at room and elevated temperatures is investigated with the aid of the comprehensive fully self-consistent optical-electrical-thermal-gain model. A standard OC GaInNAs/GaAs double-quantum-well VCSEL emitting the 1.3-μm radiation is used as a typical modern VCSEL structure. The oxide aperture is placed at the anti-node position of an optical standing wave within a VCSEL cavity. The desired single-fundamental-mode (SFM) operation has been found to be expected only in VCSELs equipped with relatively small active regions of diameters equal or smaller than 10 μm. Therefore a proton implantation used as an radial additional confinement of the current spreading from the upper annular contact towards the centrally located active region is proposed and its impact on the VCSEL performance is investigated. The above structure modification has been found to enable a radical improvement in the VCSEL performance. In particular, in this case, the SFM VCSEL operation is possible even in VCSELs with quite large active regions and for much wider ambient-temperature range than in the standard OC VCSELs.

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“…The approximate conservance of the plane and the degree of polarization is characteristic for the relatively short fibres of small 6 in the retina. For the much longer fibres of, for example, Snitxer and Osterberg (1961) this may not be the case. These remarks should be considered in the designation of modes to patterns observed in retinal receptor outer segments.…”

Section: Theorymentioning

confidence: 99%

Mode interference patterns in retinal receptor outer segments

Wijngaard

1974

Vision Research

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Abstract-Some calculated interference patterns of electromagnetic modes are given for a dielectric waveguide representative for the receptor outer segment. The results are qualitatively in accordance with observations of Enoch.Retinal receptors are lightguiding structures of relatively small dia, in which the energy is guided in patterns called modes (Enoch, 1963). These modes have a definite phasevelocity. However, generally some modes with d&rent phaseveloeities occur inside the receptor outer segment. In this case the modes interfere with a different phase at different levels along the outer segment.For some cases interference patterns of guided modes were calculated. Results qualitatively in aceordante with some observations of Enoch (1963) were obtained. THEORYThe receptor outer segment was approximated by a homogeneous isotropic circular cylindrical dielectric rod (Fig. 1). Apart from guided modes there are unguided modes which are not bound to the receptor. These unguided modes wig not be considered here. The characteristics of the guided modes are determined by the normalized frequency u = (Znpn,/l,,)JG and 8. Here d = 1 -(n:/n:); n, and n2 are the refractive indices of the inside and outside medium respectively, p is the radius of the rod and )LnC is the vacuum wavelength of the incident light. For retinal receptors the parameter S is of the order of @l, therefore the approx results for 6-0 may be used for the field of the modes (Snyder, 1969a). The amplitude with which a mode is excited may be calculated neglecting the reflected light (Snyder, 1969b). In this approximation when the light incident on the outer segment is plane polar&d, plane polarized modes and modecombinations are excited (Wijngaard, 1971). Interference effects can only be obtained when the phasevelocity of the modes is different, therefore the approximation 6 + 0 is not applicable to calculations of the phasevelocity. However, the difference in phasevelocitpbetween the modes of a plane polarized mode-combination is small enough to conserve the plane polarixation when the modes are guided along the outer segment.The author has discussed minor deviations from this result for frog rods (Wijngaard. 1971). The approximate conservance of the plane and the degree of polarization is characteristic for the relatively short fibres of small 6 in the retina. For the much longer fibres of, for example, Snitxer and Osterberg (1961) this may not be the case. These remarks should be considered in the designation of modes to patterns observed in retinal receptor outer segments.To obtain physiologically significant interference patterns the amplitudes of the modes should be calculated from the field incident on the retina. However, even for an incident plane wave this problem is complex owing to the influence of the inner segment. Therefore the field at the entrance of the outer segment was assumed to be a plane wave restricted to the outer segment with the electric field vector perpendicular to the plane of incidence. The propagation vector k of the p...

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Observed Dielectric Waveguide Modes in the Visible Spectrum*

Cited by 137 publications

References 3 publications

Directional sensitivity of the retina: 75 years of Stiles–Crawford effect

Directional sensitivity of the retina: 75 years of Stiles–Crawford effect

Current spreading modification to enhance single-fundamental-mode VCSEL operation at higher temperatures

Mode interference patterns in retinal receptor outer segments

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