We propose an efficient quantum memory scheme with natural inhomogeneous broadening in an asymmetric optical cavity. The scheme uses the strong rephasing pulses like traditional photon echo techniques rather than spectral holeburning, which enables us to have the potential implementation in a much broader range of material systems. In the condition of impedance matching to an optical cavity, we find that the input light pulse can be completely absorbed by an atomic ensemble. We also show that the quantum memory efficiency can be equal to unity even for a small optical depth of the atomic system. 相似文献
Hypercrosslinked polymers (HCPs) are currently receiving great interest due to their easy preparation, high chemical and thermal stability, and low cost. Combined with the lightweight properties and high surface areas HCPs can be considered as promising materials for gas storage and separation, catalysis, and heavy metal ions removal in wastewater treatment. This Feature Article summarizes strategies for the preparation of HCPs, comprising the post‐crosslinking of “Davankov‐type” resins, direct polycondensation of aromatic chloromethyl (or hydroxymethyl) monomers, and knitting aromatic compound polymers (KAPs). The HCPs applications, such as H2 storage, CO2 capture, and heterogeneous catalysis, are also discussed throughout in the article. Finally, the outlook of this research area is given. 相似文献
The term hydrogel describes a type of soft and wet material formed by cross‐linked hydrophilic polymers. The distinct feature of hydrogels is their ability to absorb a large amount of water and swell. The properties of a hydrogel are usually determined by the chemical properties of their constituent polymer(s). However, a group of hydrogels, called “smart hydrogels,” changes properties in response to environmental changes or external stimuli. Recently, DNA or DNA‐inspired responsive hydrogels have attracted considerable attention in construction of smart hydrogels because of the intrinsic advantages of DNA. As a biological polymer, DNA is hydrophilic, biocompatible, and highly programmable by Watson‐Crick base pairing. DNA can form a hydrogel by itself under certain conditions, and it can also be incorporated into synthetic polymers to form DNA‐hybrid hydrogels. Functional DNAs, such as aptamers and DNAzymes, provide additional molecular recognition capabilities and versatility. In this Review, DNA‐based hydrogels are discussed in terms of their stimulus response, as well as their applications.