تابعین کرام کا مقام و مرتبہ اور ان کی علمی و ادبی خدمات

After the Prophets of Allah Almighty, the most sacred class of mankind is the class of Prophet Muhammad's Companions. Those are the people who had seen the prophet of Islam with their naked eyes, remained in his companionship and got the heights of knowledge and actions and proved to be a great example of character by attaining the image of Prophet Muhammad's model of excellence. Another class which, like the companions of Prophet (pbuh), deserves such honor is the class of Tabe’en (The followers of the Companions).  Tabe'en had contributed a matchless role in the history of Islam regarding religious knowledge and literature. They had also examplary performed in social, economical, political and military services. Due to these great services they are considered the most sacred class of the Ummah after the prophet’companions. There is a list of academic and literary services ahead of the name of each person in this class. And these services are the great testimony to the greatness of these people. The prophet's companions received the religious knowledge directly from the Prophet (peace and blessings of Allah be upon him), while Tabe'en got it from the companions and then published it in the whole world. The sincere efforts performed by Tabe'en regarding Quran, Hadith, Tafseer and Islamic litrature are of so high level that no one had reached such level of sincerity in the entire history of Islam. The steps that occur after that period, regarding the development of Islamic culture are only the effects of their services. Actually ‘‘Tabe’en’’ is the only class that has spread the social, moral and spritual blessings of Islam throughout the world. That is why, it is not only the Quran that witnesses their greatness but the Prophet (peace be upon him) also praises them.

Coherent Control of Electromagnetically Induced Grating

In this PhD thesis, we investigate the coherent control of electromagnetically induced grating (EIG) through different atomic media under distinct conditions of coherence. An atom-field system which exhibits EIT acts as an EIG (atomic grating) when the traveling wave control field is replaced by a standing-wave field. The spatial modulation of the standing-wave changes the amplitude of the incident probe light field in a periodic manner similar to that as hybrid grating. The EIG and its applications have attracted researchers in various fields of science to study, for example, diffracting and switching a quantized probe field, probing the optical properties of a material, and all optical switching, routing, and light storage.Initially, we investigated the role of spatial coherence on diffraction intensity for a partially coherent incident Gaussian Schell model (GSM) beam which is diffracted from a two-level atomic grating. It is shown that the performance of the atomic grating is greatly influenced by the spectral coherence width of the partially coherent fields. It is observed that relatively large intensity of the diffracted light can be obtained via spatial coherence, beam width, interaction length, and mode index of partially coherent incident light. The scheme provides possibilities for the potential applications of atomic grating in lensless imaging using the partially coherent light field. Next, we present a scheme to realize electromagnetically induced grating in an ensemble of strongly interacting Rydberg atoms, which act as superatoms (SAs) due to the dipole blockade mechanism. The ensemble of three-level cold Rydberg-dressed (87Rb) atoms follows a cascade configuration where a strong standing-wave control field and a weak probe pulse are employed. The diffraction intensity is influenced by the strength of the probe intensity, the control field strength, and the van der Waals (vdW) interaction. It is noticed that relatively large first-order diffraction can be obtained for low-input intensity with a small vdW shift and a strong control field. The scheme can be considered as an amicable solution to realize the atomic grating at the microscopic level, which can provide background- and dark-current-free diffraction. Finally, we extend the idea of electromagnetically induced grating to exploit the realization of one-dimensional (1D) and two-dimensional (2D) electromagnetically induced holographic imaging (EIHI) in an ensemble of strongly interacting Rydberg atoms. Here, we consider two schemes for holographic imaging; the first scheme is the direct detection of holographic imaging pattern and called as electromagnetically induced classical holographic imaging (EICHI), whereas in the second scheme entangled photon pairs are employed for the imaging and it is called as electromagnetically induced quantum holographic imaging (EIQHI). Both schemes are employed to obtain 1D and 2D holographic imaging. In EICHI and EIQHI, amplitude and phase information of EIG can be imaged with controllable image variation in size. It is noticed that holographic imaging is also influenced by vdW effect present in Rydberg atoms.