Abstract

In our paper, we present data taken with optically pumped VCSELs on picosecond timescales, with time resolution given by the pulse duration of our reference pulse (300 fs). The data was obtained using DC balanced homodyne detection ¹ which provides average intensity, intensity noise strength, and two-mode intensity correlations. Figure 1 shows data taken with a VCSEL grown at the University of Arizona (NMC63) which contained two 8.5 nm ln₀.₀₄Ga₀.₉₆As quantum wells cooled to 10 K. Figure l (a) shows how spin-flip processes can populate one electron-hole spin population when only the other pin was initially populated by the pump. The intensity fluctuations were uncorrelated, as shown in Fig. 1 (b) with the two-mode second-order coherence function g⁽²⁾ at a value of 1 throughout the emitted pulse. When the pump pulse was linearly polarized, equal intensities were measured in both linearly polarized modes, as shown in Fig. 1 (c). Figure 1 (d) shows that the intensity fluctuations in the linearly polarized modes were anti-correlated. We believe that this anti-correlation comes not from mode-competition between two linearly polarized modes aligned with the crystal axes, but instead from linearly polarized emission with random orientation on each pulse, which leads to anti-correlated projections onto any two orthogonal linear polarization axes.

© 2002 Optical Society of America