Do single photons tunnel faster than light?

Experiments done in the early 1990's produced a surprising result: that single photons pass through a photonic tunnel barrier with a group velocity faster than the vacuum speed of light. Subsequent experiments with classical pulses have also revealed apparent superluminal group velocities as well as tunneling times that saturate with barrier length, a phenomenon known as the Hartman effect. In this paper we show that the measured delays are in fact cavity lifetimes as opposed to transit times. This interpretation resolves the Hartman paradox and shows that tunneling is not superluminal as widely believed.Comment: Invited Paper presented at the SPIE Conference "The Nature of Light: What are Photons?", San Diego, CA, August 26, 200

Comment on "Macroscopic violation of special relativity" by Nimtz and Stahlhofen [arXiv:0708.0681v1]

A recent paper by G. Nimtz and A. A. Stahlhofen [arXiv:0708.0681v1] makes the following claims: (1) that the authors have observed a macroscopic violation of special relativity, (2) that they have demonstrated quantum mechanical behavior of evanescent modes on a meter-length scale, and (3) that barriers are crossed in zero time, implying superluminal (faster than light), and indeed, infinite tunneling velocity. Here I suggest that all these claims are erroneous and are based on a misinterpretation of a purely classical measurement accurately described by Maxwell's equations.Comment: This is a comment on a paper posted on the arXiv on August 5, 2007 and reported in the New Scientist on August 18, 200

Dynamics of resonant optical waveguide semiconductor laser arrays

A propagation model is presented for the dynamics of antiguided semiconductor laser arrays. The model takes into account diffraction, carrier diffusion, spatial hole burning, and carrier‐induced antiguiding. Numerical results reveal a variety of spatiotemporal behaviors ranging from stable, quiescent operation to periodic and erratic intensity oscillations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71202/2/APPLAB-62-25-3226-1.pd

Operation and stability of antiguided flared amplifiers

We present a propagation model for the dynamics of antiguided flared amplifiers. This model takes into account diffraction, carrier diffusion, spatial hole burning, carrier‐induced antiguiding, and spontaneous emission. Numerical results demonstrate that flared antiguides are significantly less susceptible to noise induced filamentation than broad area devices. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70540/2/APPLAB-68-18-2472-1.pd

The effect of nonlinear gain on the stability of evanescently coupled semiconductor laser arrays

We show that nonlinear gain saturation can enhance the stability of evanescently coupled semiconductor laser arrays.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71325/2/JAPIAU-73-1-459-1.pd

Extremely high‐frequency self‐pulsations in chirped‐grating distributed‐feedback semiconductor lasers

We show that an asymmetrically chirped, single‐section distributed‐feedback (DFB) laser is capable of sustained self‐pulsations at frequencies in excess of 200 GHz. These pulsations arise from mode beating and are absent in uniform or symmetrically chirped DFB lasers. For sufficiently large coupling constants, the pulsation frequency can approach a terahertz. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70703/2/APPLAB-69-20-2989-1.pd

Propagation model for the dynamics of gain‐guided semiconductor laser arrays

A model is presented for the spatiotemporal dynamics of gain‐guided semiconductor laser arrays. The model goes beyond coupled mode theory and treats the array as a single entity. Numerical simulations of twin‐stripe gain‐guided arrays yield stable or pulsing outputs, depending on array parameters.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70023/2/JAPIAU-73-1-462-1.pd