Ultrafast all-optical switching at 1.55μm using an organic multilayer device

Abstract

We report ultrafast all-optical switching at optical communication wavelength using a device with a layered structure containing organic films. Spin-coated layers of di(benzofuranonyl)methanolate (BM) derivative are formed alternately with vacuum evaporated layers of germanium (II) oxide. An optical Kerr shutter is constructed using this BM multilayer with 1.55μm signal and 1.63μm gate pulses of 100fs time durations. As a result, optical switching with signal-to-noise ratio over 20dB is attained at gate-pulse intensity above 30pJ∕μm2 and a response time comparable to pulse width is observed. The BM multilayer could be an efficient optical communication device for parallel data processing.

Increase in exciton decay rate due to plane-to-plane interaction between cyanine thin films

“…1,2 In particular, optical switches based on saturable absorption have been extensively studied using various materials including semiconductor quantum dots, [3][4][5][6] quantum wells, [7][8][9][10] and organic materials. [11][12][13] Such switches require both large intensity modulation and ultrafast response, which has been a key issue. While the modulation magnitude depends on a decrease in the absorbance because of the state filling effect, 14 the ultrafast signal decay in nanostructured semiconductors relates to several factors, e.g., the intersubband transition, [15][16][17][18] spin relaxation, 7,[19][20][21] and carrier tunneling.…”

Influence of self-diffraction effect on femtosecond pump-probe optical Kerr measurements

“…For the last few decades, research of ultrafast all-optical switch has been stimulated by its high-bit-rate handling of optical signals for the need of future integrated optical system [1][2][3]. As the two main parameters characterizing the optical switching properties of materials, a large third-order nonresonant optical nonlinearity and a fast response are the most important properties for the realization of such all-optical switches.…”

Near infrared absorbing benzobis(thiadiazole) derivatives: computational studies point to biradical nature of the ground states

“…Because these absorb in the near infrared region, these dyes are also referred to as NIR dyes 1–4. Some promising NIR dyes are the squarylium dyes, croconate dyes, and recently synthesized derivatives of di‐(benzofuranonyl)methanolate (BM dye) all of which contain the meso‐ionic oxyallyl substructure 1–4, 12–14. We have recently carried out high level computational studies of these dyes and attributed the NIR absorption to the singlet biradicaloid character of the oxyallyl substructure 26–31.…”

“…Here computational chemistry based on quantum chemical theories, which are replacing the earlier empirical rules, is playing a major role in understanding the dyes post priori experiment or in suggesting modifications, a priori synthesis suitable to the applications 1–4. Recent studies of the organic dyes have concentrated in the absorption range greater than 700 nm, as these are useful in telecommunications based optical devices, in medicine, semi‐conductor lasers, organic electroluminescent devices, etc 10–25. Because these absorb in the near infrared region, these dyes are also referred to as NIR dyes 1–4.…”